Non-US projects are handled differently. I don't need an amazon payments account like all US projects creators do, and the money goes directly into my back account minus a merchant fee. I don't know what CC merchant they are using though?

I have never funded a kickstarter... until now. But this device is a darn useful tool to have and I could not pass up the opportunity. It won't be used often, but when it is needed it will be like gold. A bit like my digital frequency meter - rarely used, but when you need it you need it. A Christmas present to me from me - something I always wanted! :)

Would have liked to found the Project and get one of those nice mCurrets, but Kickstarter doesn't want my Money. On Pozible i payed happily via PayPal to get those nice Rulers but Kickstarter only acceps Kredit Cards. Don't have a Card...

Would have liked to found the Project and get one of those nice mCurrets, but Kickstarter doesn't want my Money. On Pozible i payed happily via PayPal to get those nice Rulers but Kickstarter only acceps Kredit Cards. Don't have a Card...

Been on the fence about picking a uCurrent up for some time now - the gold edition just had that extra 'Bling' factor. I can get a heavy Goldchain and wear it around my neck when I'm not using it - Awesome Dave!

I guess it won't matter now that you crossed the threshold but saying it anyway.

There's a large gap between 5$ and the next option, 79$ ...

Maybe you could have offered something like do-it-yourself ( no case, just pcb and parts in a bag along with a few ml of paste, cheap to mail and all that) for those that are willing to make it themselves (no refunds, no support offered etc) for around 25-40$

Or 10-20$ for (tip dave, get only a bare pcb as a gift) along a list of parts or alternative for parts so someone could buy those from farnell/newark/digikey

79 australian dollars is a bit above what I would pay for uCurrent at this time

I guess it won't matter now that you crossed the threshold but saying it anyway.There's a large gap between 5$ and the next option, 79$ ...Maybe you could have offered something like do-it-yourself ( no case, just pcb and parts in a bag along with a few ml of paste, cheap to mail and all that) for those that are willing to make it themselves (no refunds, no support offered etc) for around 25-40$

Options = more work.Normal kits are a bad idea, and SMD kits are a very bad idea!

Quote

Or 10-20$ for (tip dave, get only a bare pcb as a gift) along a list of parts or alternative for parts so someone could buy those from farnell/newark/digikey

I thought about that, but ultimately that will just mean more support on my end, just like with kits.I just want to sell some uCurrents, so ultimately anything else detracts from doing that and getting on with other stuff.You can always download the PCB files and get your own board made.And some of these parts are not in stock BTW.

Quote

79 australian dollars is a bit above what I would pay for uCurrent at this time

First Kickstarter backing here too. Just doing my part for ya Dave, congrats on the success. :clap:I bet you never thought you would be doing this a few years ago, did ya?OK, now that this campaign is funded, can you get back to the microSupplies? :-DD I really want one.Oh wait, that will be next years Kickstarter..... :-+ March or April maybe?

Only they look at non-english speaking countries, like they don't exist.

Maybe non-english countries just don't use it much? Perhaps Dave will help them take notice.

First it was amazon payments. It was impossible to get it outside the US. Now it is not amazon payments, now you "only" need a credit card. Which, because the banking system works differently, not a lot of people have. We are fine with debit cards, and paying with our own money. What is wrong with paying with paypal? And you cannot post campaigns, only if you are from USA, UK, Canada, Australia or that tiny little island next to it. I would use it. Only I cannot pay, and cannot get money for projects. And they put import charges on stuff, and shipping charges, handled individually. You end up paying 50% more even if you can, as other people already showed.

Only they look at non-english speaking countries, like they don't exist.

Maybe non-english countries just don't use it much? Perhaps Dave will help them take notice.

First it was amazon payments. It was impossible to get it outside the US. Now it is not amazon payments, now you "only" need a credit card. Which, because the banking system works differently, not a lot of people have. We are fine with debit cards, and paying with our own money. What is wrong with paying with paypal? And you cannot post campaigns, only if you are from USA, UK, Canada, Australia or that tiny little island next to it. I would use it. Only I cannot pay, and cannot get money for projects. And they put import charges on stuff, and shipping charges, handled individually. You end up paying 50% more even if you can, as other people already showed.

is a shame they dont support paypal, i would have preferred this too as i have funds in it already. I guess paypal take too much for the processing fee, more than visa or mastercard.

But i also have a pre-paid mastercard and a visa debit card, neither of which are 'credit cards', are these options not available in Belgium?

It's more like "We don't like to obey Paypal!". If for example a Cuban runs a kickstarter Paypal would freeze Kickstarter's account. Exactly that happened here when a large local retailer (1800 shops) offered Cuban cigars in his online shop.

Good to see the campaign being so successful. I had to get in on it, just because... it's Dave's campaign! Oh plus the device is very handy to have. Maybe a collection of all the µXXXX series products, EEVblog brand. :)

But if that happens there're still the other options to fall back to and some people might want paypal. Its still unsound business practise.

@Dave: Will you post the Kickstarter video on your channel as well? Btw: You should have explained first what the µCurrent does before referring to your article. People have a short attention span nowadays. If "read my article to see what it does" if the first thing they hear, they go away even if you give them a summary afterwards. (How should they see it coming?) They don't know the awesome ::)

...@Dave: Will you post the Kickstarter video on your channel as well? Btw: You should have explained first what the ?Current does before referring to your article. People have a short attention span nowadays. If they here first "read what it does" they go away even if you give them a summary afterwards. ::)

It doesn't seem to be the case for this campaign. Maybe because the audience is already interested, and because of the nature of EEs?

I agree most of the audience is already interested. They know Dave, know what the µCurrent does and have been waiting for a new instalment. But some window shoppers might be lost. You underestimate the number of impulsive people.

Some campaigns have lost me in the past simply because their videos didn't get to the point of "what is it and why would I want it" quickly enough. Especially if I'm just taking a quick break from work and my concentration has been mingled by 8h+ of programming. I assume the mighty D. doesn't rely on income from a few sells, but they're still nice to have.

Bummer, I missed the first production run. Ah well, I'll buy a regular one for the premier price and hope that Dave wants run his reflow oven all Christmas. If not, no big deal, he can use the extra money to buy more chocolate and extra time to consume it.

Now trending to $450,000. Seems unlikely but who knows! Definitely my favorite kickstarter to date. :-+

I think it would be nice if you had a small reward to get a few rulers. I'd easily add a couple of rulers to my order for a few buck to give away etc, but the only (reasonable) option with rulers is already filled up.

Many have talked about the need of a CC, or how the banks are different, or how they can't use a debit card. Here is my experience:Had no problem using my virtual NON credit card issued from a Ukrainian Bank, shipping to the Ukraine.This is my second kickstarter item; on the other one I used a debit card with MasterCard logo and had no issue with that one either.

I've always sort of wondered. If there's something so infinitely as useful sounding as a uCurrent, why Fluke/Agilent/etc integrated that function by now? (This is meant as a genuine question, not a rhetorical one)

I mean if one man can roll his own, why can't they? Is it just because in order to make it accurate, they have to leave out some protection which will cause warranty claims?

Also (not trying to jinx him) but I wonder with the speed in which this is funded if it will raise a red flag?

Also the $5 option that gives you the ability to "troll the comments section if that's your thing" >:D

I suspect some here would gladly pay $5 to continue some locked thread discussions. :-DD

@Dave: Will you post the Kickstarter video on your channel as well? Btw: You should have explained first what the µCurrent does before referring to your article. People have a short attention span nowadays.

Didn't I explain what it does?, pretty sure I did!I wasn't going to spend another few minutes in the video explaining burden voltage in detail.

I've always sort of wondered. If there's something so infinitely as useful sounding as a uCurrent, why Fluke/Agilent/etc integrated that function by now? (This is meant as a genuine question, not a rhetorical one)

Because it's ultimately quite a niche thing. For the majority of current measurement uses you can usually "get by" with regular multimeters, DIY shunt resistors, and upping your supply on your bench supply to compensate for the burden voltage.The popularity of it honestly surprises me.

I've always sort of wondered. If there's something so infinitely as useful sounding as a uCurrent, why Fluke/Agilent/etc integrated that function by now? (This is meant as a genuine question, not a rhetorical one)

Because it's ultimately quite a niche thing. For the majority of current measurement uses you can usually "get by" with regular multimeters, DIY shunt resistors, and upping your supply on your bench supply to compensate for the burden voltage.The popularity of it honestly surprises me.

Maybe it's because you're excellent at selling it to us? :)

To be honest, it doesn't surprise me one bit, as:

More and more of us are designing battery powered products where maximum life is important.

If you're designing said product, the optimisations that can be made and extra life given to the battery could mean the product is far more competitive and pay back the cost of the unit quickly enough.

Ideal emergency weapon when battery life is terrible and the boss is breathing down the neck wanting to know why you can't get the battery life as good as the competition.

I reckon most engineers much prefer to quickly plug in a black box that can be trusted than fiddling around 'engineering' our own solution/work-around. Especially when time is short and you need something that plugs in and 'just-works'.

Many of us don't have a problem paying it to you as it will directly support EEVBlog! Of course if we get a really useful reward out of it, then it makes it very easy to explain to the other-half why you've just spent $100. Going by the rate the campaign is currently going, it could be self funded for a few years...! ;D

From twitter: Kickstarter has some interesting stats. 9% have bought via KS (so presumably not fans). Only 50% watched the entire video.

I think people are not watching the video since it is bogged down.I tried twice to watch the video on kickstarter. The first time it refused to start and just kept trying to buffer. I tried a few hours later (from a different computer) and It kept playing a few seconds at a time and then buffering for a few minutes. Both attempts were fails to complete.

While it most likely won't happen, is there any possibility to bump the number of first production run units? I missed getting one by seconds :( If not, I am just happy that I will eventually have one :)

While it most likely won't happen, is there any possibility to bump the number of first production run units? I missed getting one by seconds :( If not, I am just happy that I will eventually have one :)

Well, to be honest that number was a bit of a wank. I always planned to do at least 500 units anyway, and it's likely all the boards will go through at once anyone, not just 200.So it really depends on how tired I am of shipping the first 200 units as to when I give the rest of the job to someone else, but I guess I have to stop somewhere?

I feel sorry for Dave already, after seeing him post a number of those uRulers recently! I really wanted one of those but couldn't afford it at the time :(

As a question for Dave, would you mind sharing the part number for the connector used in the uCurrent? Just something of interest... plus I always have difficulty in finding good connectors, in general, for decent value anyhow.

Coincidentally I'm in the process of setting up my new corporate bank account today, I hope I can change my bank details in KS to match. They don't let you edit this stuff after the fact, I'll have to speak to a human...I'm paying oodles to my accountant to suck all the data from my bank account and manage it, this will be a good test (or a plain nightmare) if all the transactions come in individually... :scared:

As a question for Dave, would you mind sharing the part number for the connector used in the uCurrent? Just something of interest... plus I always have difficulty in finding good connectors, in general, for decent value anyhow.

I went through a LOT of connectors to find the right one for this, there are lot of crap ones out there, they might all look the same, but some are just plain hopeless.Franky from the forum sourced this one for me, I don't have a part number for it.

Coincidentally I'm in the process of setting up my new corporate bank account today, I hope I can change my bank details in KS to match. They don't let you edit this stuff after the fact, I'll have to speak to a human...I'm paying oodles to my accountant to suck all the data from my bank account and manage it, this will be a good test (or a plain nightmare) if all the transactions come in individually... :scared:

I doubt that, i would have thought KS are holding the money in escrow and will international transfer it in one lump to you?

Dave, if you would be so kind as to declare the item as a gift valued at around $10 that would be superb! :)

Dave has mentioned on several occasions (prices for contests) that he will not lie/break the law in the customs forms. I think the customs forms for these will be printed out, so no unclear handwriting either. Ebay sellers usually just garble something in there, usually that results in stuff coming through customs without problems.

Would have liked to found the Project and get one of those nice mCurrets, but Kickstarter doesn't want my Money. On Pozible i payed happily via PayPal to get those nice Rulers but Kickstarter only acceps Kredit Cards. Don't have a Card...

GreetingsJanaha :'(

.and you don't know anybody else who has, who you could give cash to ? :-//

I went through a LOT of connectors to find the right one for this, there are lot of crap ones out there, they might all look the same, but some are just plain hopeless.Franky from the forum sourced this one for me, I don't have a part number for it.

*chuckles* Many thanks either way! I have only recently started out in electronics so you can probably imagine how daunting of a prospect this can be when it comes to finding connectors of /any/ kind...

µCurrent BERYLLIUMCOPPER Edition would be even better because of minimum contact resistance, it would finally make µcurrent a true metrology instrument. Would include beryllium copper binding posts and switches with beryllium copper contacts.

As a question for Dave, would you mind sharing the part number for the connector used in the uCurrent? Just something of interest... plus I always have difficulty in finding good connectors, in general, for decent value anyhow.

I went through a LOT of connectors to find the right one for this, there are lot of crap ones out there, they might all look the same, but some are just plain hopeless.Franky from the forum sourced this one for me, I don't have a part number for it.

Shameless plug (no pun intended) for myself here... I am ordering some more of these gold plated binding posts from the supplier and will be making them available through my eBay store soon. I only ordered a few extra pairs when Dave asked, should have ordered more... :palm:

BTW, to the best of my knowledge the part number for these is "306-H". No idea how universally used this number is though.

I don't mean to sound disparaging, but aren't those just pretty standard gold speaker binding posts like these?

Sure. But the trick is in finding the right one that has a suitable keying part that locks on the PCB, a wire hole, colour ID rings that don't fall off, the right depth for banana plugs, and with quality material (copper is more expensive), and all that at a suitable price. It was not easy I can assure you.

In most countries, the state won't bother to collect tax and customs on that amount.

Let me explain something to you. For every item over 77 - 77.5 AUD you have to pay customs fee and tax, in my country. Everything under that, can be imported without customs fee and tax. The problem is that customs officers are bunch of bastards. They do not give a f... about how much something costs or how much you actualy paid for it. They will estimate the value of the item themselves. It does not meter that you bought something on Ebay for 30 euros, they will tell you that the same item costs 65 euros in Serbia and that you have to pay the customs fee and taxes for it. Or give them bribe...

But seriously, I hope Dave at some stage does a Kickstarter project for the µSupply power supply project, as that would be very useful item...

Dave, you hearing this? I suggested this June 2012. Hopefully, with the recent success of your last two crowd-sourcing projects, you will now have the confidence to finish the µSupplies. I hope you do.

The fuge? Really? Thought that was a lame stereotype, but okay. I was very lucky with customs in Austria. When I ordered my bench meter for 500,- € from the US, it came straight to me, no fees. Same for the whole of my china orders. There must have been at lest 20 of 80€+ and never had a problem. In Germany however, I had to drive though the whole fudging city of fudging Munich to get to the customs office for fudging $12.50 and less. I showed them the bill, a copy of which was also on the outside of my package, but never mind, and they said: "okay, you can take it." Great! what did you need me for, again?! Happened at least 4 times. (Only he didn't say fudge).

My original uSupply was done in 2009. I could have pushed it out then, but I didn't, because it's a pet project of mine (as all my projects are).It's not all just about money and success in crowd funding. It will come out when it comes out.

In Spain they want to collect taxes also for the shipping. They even try to justify why this makes perfect sense. If the shipper fills the custom declaration with just the product price, you may get away with it, but if you show the full bill, even if the shipping is a separate item, they'll calculate taxes over the total amount.

With China it isn't usually an issue, as the shippers usually fill custom declarations with whatever concept and value they like that particular day.

Hi!I wanted one of the first production run, unfortunately Kickstarter didn't want me to pay with Paypal. I ordered a credit card just because of you, Dave. I'll be living under a bridge, but at least, I'll be able to order a uCurrent soon!

In Spain they want to collect taxes also for the shipping. They even try to justify why this makes perfect sense. If the shipper fills the custom declaration with just the product price, you may get away with it, but if you show the full bill, even if the shipping is a separate item, they'll calculate taxes over the total amount.

With China it isn't usually an issue, as the shippers usually fill custom declarations with whatever concept and value they like that particular day.

In the UK, and I think all the EU, the threshold of whether it gets charged is on the declared goods value (I think around GBP18 for goods, GBP36 for giftsIf it exceeds that they charge import duty (usually minimal for electronics) and VAT on the declared goods value PLUS the value of postage PLUS the handling fee (GBP8 for Royal Mail in UK)

The argument is that if you buy something in a local shop, the price includes the cost of getting it to that shop.

Unfortunately a lot of sellers (especially in countries with high tax-free thresholds like US and Australia) don't understand this, and include shipping cost on the customs label, so it gets charged double.

For low value goods, it is especially annoying if the seller's inclusion of shipping cost takes it over the duty free threshold. as this can nearly double the total.

Here the customs ask receipt of what you actually paid. The customs form is secondary information, ss it is unreliable anyway. The chinese try to make me a favor and mark stuff as gift (trying to make me commit fraud), the shipping may or may not be included there etc.

In the UK, and I think all the EU, the threshold of whether it gets charged is on the declared goods value (I think around GBP18 for goods, GBP36 for gifts

I wish these "rules" were easy to find.

I sell an item for $15, and often get asked to mark it on the customs form as $2-$3. I'm not sure if that's the level, or if it's just a knee-jerk reaction on behalf of the buyer.

In the US, we don't pay import duties(yea, we're awesome like that!) - so I don't even know how it works???? I assume you get a notice in the mail that you have a package, but you need to come pick it up. Then when you arrive, they calculate what you owe?

I'm sure that doesn't leave a pleasant experience for the buyer. 1.) they have to go pick it up 2.) they have to *pay* to pick it up.

Oh, a question for Dave. I know you've mentioned that you didn't design fuse protection into the uCurrent so as to keep the burden voltage low. What kind of effect would a fuse have on the burden voltage? And if say, you were to add a fuse, what would you spec it out as? I assume about 2 amps, and a fast blow type?

Unfortunately a lot of sellers (especially in countries with high tax-free thresholds like US and Australia) don't understand this, and include shipping cost on the customs label, so it gets charged double.

I've never put the shipping cost. The CN22 customs form just says "value", it makes no indication to put the shipping value too, so I don't why anyone would think to include that?

In the UK, and I think all the EU, the threshold of whether it gets charged is on the declared goods value (I think around GBP18 for goods, GBP36 for gifts

I wish these "rules" were easy to find.

I sell an item for $15, and often get asked to mark it on the customs form as $2-$3. I'm not sure if that's the level, or if it's just a knee-jerk reaction on behalf of the buyer.

In the US, we don't pay import duties(yea, we're awesome like that!) - so I don't even know how it works???? I assume you get a notice in the mail that you have a package, but you need to come pick it up. Then when you arrive, they calculate what you owe?

I'm sure that doesn't leave a pleasant experience for the buyer. 1.) they have to go pick it up 2.) they have to *pay* to pick it up.

taxes + brokerage fee + possibly another fee for them to front the money for you.

Oh, a question for Dave. I know you've mentioned that you didn't design fuse protection into the uCurrent so as to keep the burden voltage low. What kind of effect would a fuse have on the burden voltage? And if say, you were to add a fuse, what would you spec it out as? I assume about 2 amps, and a fast blow type?

You could include one on the Amps range if you wanted, 5A would do. But if it's an SMD type, then it's as much a PITA to change as the resistor is.I've included a fusible track just in case.It would need to be around 5A say in SMD to get the same order as the switch and shunt value. But now you have 3 elements instead of 2 contributing.For the uA range you'd need say a 250mA fuse tops, and that would be ok too. But same problem with SMD.To solve the PITA factor, you'd have to use a polyswitch and they are just too high in value.Through hole sockets are out of the question, so you'd need an SMD socket, then add in the socket contact resistance too. It just gets a bit ugly.

In the US, we don't pay import duties(yea, we're awesome like that!) - so I don't even know how it works???? I assume you get a notice in the mail that you have a package, but you need to come pick it up. Then when you arrive, they calculate what you owe?

If it comes by mail, they send you a notice saying that you have a package so you can either authorize the post office to do the dispatching for you and bill you for both taxes and the handling fee, or you can go to the airport and do it by yourself, which it'll allow you to get your package quicker but can take you a whole morning.

Usually couriers (UPS, DHL, FedEx) are much more convenient for handling this issues. Packages from DigiKey and Mouser may arrive 36 hours after placing the order with customs cleared.

Unfortunately a lot of sellers (especially in countries with high tax-free thresholds like US and Australia) don't understand this, and include shipping cost on the customs label, so it gets charged double.

I've never put the shipping cost. The CN22 customs form just says "value", it makes no indication to put the shipping value too, so I don't why anyone would think to include that?

Because, especially in countries with high exempt limits, they often won't have direct experience of paying charges, and don't understand why it matters if they declare $20 or $30 on the form - I've frequently had stuff with the total on the CN22, or an arbitary (higher) value, especially from the US.

In the UK, and I think all the EU, the threshold of whether it gets charged is on the declared goods value (I think around GBP18 for goods, GBP36 for gifts

I wish these "rules" were easy to find.

I sell an item for $15, and often get asked to mark it on the customs form as $2-$3. I'm not sure if that's the level, or if it's just a knee-jerk reaction on behalf of the buyer.

In the US, we don't pay import duties(yea, we're awesome like that!) - so I don't even know how it works???? I assume you get a notice in the mail that you have a package, but you need to come pick it up. Then when you arrive, they calculate what you owe?

I'm sure that doesn't leave a pleasant experience for the buyer. 1.) they have to go pick it up 2.) they have to *pay* to pick it up.

In Finland, there is no import duty for most stuff, but imported stuff is subject for sales tax. If the threshold is exceeded or customs takes it anyway (they don't believe the Chinese statement "gift, value $1"), I get a notice in the mail. I go to the customs web site, fill a form and attach some proof about how much I paid (e-mail or paypal receipt or something like that). I submit the form for processing. Sometimes the processing takes a second, sometimes an hour; I guess there is some kind of an algorithm deciding if it is processed automatically or manually. When it is processed, I get e-mail. behind the link there is the customs decision and a link to pay the taxes (If I can show that the threshold was not exceeded, I don't need to pay). If I don't dispute the decision, I pay electronically, and customs computer release the package. The next day the postman brings the package (if it is small) or a notice that I can collect it from the local post office.

Would be it possible to do like for the Smoothieboard (http://www.kickstarter.com/projects/logxen/smoothieboard-the-future-of-cnc-motion-control)?

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Shipping:We will be shipping the Smoothieboards from two places:

Oregon, in the United States

France, in Europe

If you are in Europe or the US shipping is free.If you are somewhere else in the world please add $15 to your pledge to cover the extra shipping cost.

After getting a good response to their offer, they changed the shipping rules for EU backers:instead of shipping Smoothieboards from the US, they decided to ship them also from inside Europe.In a such way importing duties/taxes/... are zero because some pious souls have already imported to Europe the boards. Surely the good response to Smoothieboard gave ample space to directly cover for the following bulk expenses:- USA to EU shipping- paperwork needs- export/import duties - shipping from EU to the customers

I hope Dave will get such good results with his kickstart to be able to offer a similar deal.

Anyone in this forum who have expertise/competence/proved seriousness to give such type of service?

A little bit free advertising for Dave's µCurrent from a well known German IT news site: http://www.heise.de/newsticker/meldung/uCurrent-Gold-Multimeter-Praezisionsadapter-2068640.html (http://www.heise.de/newsticker/meldung/uCurrent-Gold-Multimeter-Praezisionsadapter-2068640.html) :-)

I saw you added 10 more hand-built editions—I was interested not so much in you as a pick-and-place machine, but the add-on of a µRuler which I gather comes with the hand-built editions. Kind of itching to get one of those: my big engineering flaw is the complete inability to grok scale, so when I'm designing, I can't get my head around what's a 0.1mm hole versus a 0.3mm hole and what would fit in each; hence, the ruler would come in oh so handy.

Ah well, c'est la vie—I put in a "donation" for a µCurrent standard with a couple extra bucks in case the shipping cost changes ... looking forward to the device and I guess I'll just have to spin my own ruler somehow (I never did figure out if it's indeed OSHW ...)

A little bit free advertising for Dave's µCurrent from a well known German IT news site: http://www.heise.de/newsticker/meldung/uCurrent-Gold-Multimeter-Praezisionsadapter-2068640.html (http://www.heise.de/newsticker/meldung/uCurrent-Gold-Multimeter-Praezisionsadapter-2068640.html) :-)

"A Bit"... it's just the single most important German IT mag :)Congrats Dave :)

Oh, a question for Dave. I know you've mentioned that you didn't design fuse protection into the uCurrent so as to keep the burden voltage low. What kind of effect would a fuse have on the burden voltage? And if say, you were to add a fuse, what would you spec it out as? I assume about 2 amps, and a fast blow type?

You could include one on the Amps range if you wanted, 5A would do. But if it's an SMD type, then it's as much a PITA to change as the resistor is.

Not if it was one of these (http://www.digikey.co.uk/product-detail/en/0154005.DR/F1228TR-ND/183358)(http://uk.farnell.com/productimages/farnell/standard/42422830.jpg)

Alternatively, if the aim is to protect an expensive/hard to get precision shunt resistor, maybe add a small sacrificial low-value 1206/0805 resistor to protect it - cheaper than a fuse, and easy enough to replace.

A little bit free advertising for Dave's µCurrent from a well known German IT news site: http://www.heise.de/newsticker/meldung/uCurrent-Gold-Multimeter-Praezisionsadapter-2068640.html (http://www.heise.de/newsticker/meldung/uCurrent-Gold-Multimeter-Praezisionsadapter-2068640.html) :-)

Here is what the article says (I kept the "Germanisms" for fun):

Quote from: heise-online

"The ?Current Gold is a precision adapter to extend the measurement range of conventional multimeters. For example, with help of the adapter one can measure the standby and rest current of micro controllers or energy harvesting projects in the nano-ampere range with great accuracy.

The device was designed by the Australian David Jones. Who has made a name for himself in the maker community by means of his own website and youtube channel (called EEVBlog). Since his original ?Current has been sold out for quite some time, he took the opportunity to improve upon the design and founded a Kickstarter campaign to fund production and sales. The price, shipping included, is just shy of 60 Euros. First deliveries are planned for March 2014.

The ?Current adapter is open source hardware. However most makes will not have the necessary, very expensive, equipment necessary to test there copy. Dave Jones mentions that the whole manufacturing process will take place in Australia in order to support local business. Jones explains the method of operation in his own article.

The result displayed on you meter translates to one mV per mA, ?A or nA. Meant here is that an exemplified display reading of 10 mV on your multi meter corresponds to 10 mA, 10 ?A or 10 nA depending on the ?Current's setting. The quality of the multi meter in use, of course, still plays a role in the measurement, but Jones claims a resolution of 100 pA even for a 3-1/2 digit multimeter. Accuracy is between +/- 0.1% for the mA range. Below that +/- 0.05 (?A and nA) are listed.

Additionally the ?Current requires a CR2032 lithium cell. The cell is not included due to restrictions on their export. The design does not have any protection against over current, because the resulting voltage drop caused by the instrument is meant to be as low as possible. The multimeter itself though is still protected by its own built in fuse, only the adapter might sustain damage (overload) if not handled correctly."

-Translated by con-f-use

Nothing interesting in it except for the whole "Average Joe can't test that crazy Aussie bloke's claims of accuracy"-part.

Nothing interesting in it except for the whole "Average Joe can't test that crazy Aussie bloke's claims of accuracy"-part.

Correct me if I am wrong but I think there were trying to say that while its entirely open source that if you build it you don't have the ability to check if the device you built is as accurate as the ones that dave is making.

Kickstarter is refusing to accept my US credit/debit card, even after calling my bank and having them "open the card" for overseas payments through the funding period. Is anyone else having this problem?? Am I going to have to live with just my plain old non-gold uCurrent?!?! :scared:

@µCurrent as µVoltageI'm considering to misuse the µCurrent as generic small signal preamp ...(It's simply a nuisance that so often when one wants to use some precision sensor it needs a preamp to be useable)... maybe by bodging in a switch instead of R12 (270R) in front of the opamp... But looking at the board-image I really worry about the tiny pads down there..... In short: I'd love to see a nice, small, affordable precision preamp-board be spun - considering your outreach into the community the volume should be enough to bring down the initial costs to affordable levels... and by adding some general filtering capabilities such a product would surely simplify many hobbyists and engineers lifes :) ... µVoltage µPreAmp µFilter µAmp µBBB (bread board breakout)..

@Battery/Consumption:How much current does the µCurrent Gold take from it's coin-cell while running?50h+ runtime on ~225 mAh ... something around 4.5 mA? (or did I forget to consider the low V dropout point)

I've got a few CR123A 3V Li batteries here... like used in modern LED flashlights... 1600 mAh + ... is there enough room in the case to fit one of those there? (That would easily give some 14 days of continuous use and even be cheaper on the money/mAh scale) ;D

Kickstarter is refusing to accept my US credit/debit card, even after calling my bank and having them "open the card" for overseas payments through the funding period. Is anyone else having this problem?? Am I going to have to live with just my plain old non-gold uCurrent?!?! :scared:

JS filter (Noscript)?I had to allow a sh**load of JS sites for the CC# verification step...

Kickstarter is refusing to accept my US credit/debit card, even after calling my bank and having them "open the card" for overseas payments through the funding period. Is anyone else having this problem?? Am I going to have to live with just my plain old non-gold uCurrent?!?! :scared:

JS filter (Noscript)?I had to allow a sh**load of JS sites for the CC# verification step...

No, I'm not blocking anything, I've tried on Chrome and Firefox. it seems to make it through trying to authorize because it tells me that it's declined :( (and yes, the card does work elsewhere)

Kickstarter is refusing to accept my US credit/debit card, even after calling my bank and having them "open the card" for overseas payments through the funding period. Is anyone else having this problem?? Am I going to have to live with just my plain old non-gold uCurrent?!?! :scared:

JS filter (Noscript)?I had to allow a sh**load of JS sites for the CC# verification step...

No, I'm not blocking anything, I've tried on Chrome and Firefox. it seems to make it through trying to authorize because it tells me that it's declined :( (and yes, the card does work elsewhere)

Hm, maybe you did try ordering 2500 AUD version and hit your CC-Limit? (just joking) ... Well, my German Visa CC went OK (some hours ago) so my second best guess is that you're not really from the US but from North Korea, Afghanistan, Iran or Syria and the NSA did put your (or a similar) name on a top secret no-buy-stuff-from-aussie-guys list... ::)... but my only suggestion left is that you get in touch with Kickstarter's support on that issue - they probably know best what's happening.

PS: Backers went from 609 to 611 while typing this ... so I guess the problem does not affect everybody

In short: I'd love to see a nice, small, affordable precision preamp-board be spun - considering your outreach into the community the volume should be enough to bring down the initial costs to affordable levels... and by adding some general filtering capabilities such a product would surely simplify many hobbyists and engineers lifes :) ... µVoltage µPreAmp µFilter µAmp µBBB (bread board breakout)..

I do have these in mind.

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How much current does the µCurrent Gold take from it's coin-cell while running?

2.5mA or something like that. I'm using a new higher efficiency led.

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I've got a few CR123A 3V Li batteries here... like used in modern LED flashlights... 1600 mAh + ... is there enough room in the case to fit one of those there? (That would easily give some 14 days of continuous use and even be cheaper on the money/mAh scale) ;D

Kickstarter does not charge the card now, only after the project is funded. They may be doing an Auth or some sort of fraud check now but I dubt it. Even more being an US company dealing with an US CC. I'd call them.

did you already publish the schematic and BOM of the new design somewhere?

The info is on my project page:http://www.eevblog.com/projects/ucurrent/ (http://www.eevblog.com/projects/ucurrent/)

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Your article for the old version led to some confusion also on the German heise online site (Heise also publishes the - here - famous c't magazine).The worse specification from the old article is assumed valid for the new design also.Publishing the correct / updated informations would perhaps clarify everything.

I have no plans to update the article, as the point is it's the\ original silicon chip article. The new specs are pretty clear on the project page and Kickstarter.

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PS: Just found out, that you were using a CSM2512 metal foil precision shunt, from Vishay Precision. (about 6AU$ @ 1000EA)Wow, that's really a big improvement over the old design. Quite sophisticated.

Yes, not cheap.

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But I'm still curious, which ChopAmp you've used, or which circuitry, to achieve that 300kHz BW @ gain = 100...Must be a 30MHz UGBW type.

I was going to suggest (if it isn't too late for a board rev) having optional mounting pads for SMD fuse holders like Mike suggested (e.g. Littelfuse NANO2).Would be great upgrade that people could do by cutting a couple of (otherwise fusible) traces and mounting these between R1 & SWA-1A, and between R1 & R9.BTW, is R9 connected to the correct terminal of R1? Isn't that putting the uA range through the Kelvin sense terminal?

Alternatively, if the aim is to protect an expensive/hard to get precision shunt resistor, maybe add a small sacrificial low-value 1206/0805 resistor to protect it - cheaper than a fuse, and easy enough to replace.

For the beefier mA shunt instead of my fusible track, you'd have to use a smaller size for it to blow first. So say 0603 which a typical 0 ohm jumper version has a typical 1A rated current at up to 50mOhms. So possibly up to 5 times higher burden voltage than the shunt.http://www.yageo.com/documents/recent/PYu-RC0603_51_RoHS_L_4.pdf (http://www.yageo.com/documents/recent/PYu-RC0603_51_RoHS_L_4.pdf)0805 is better on max current, but same "<50miliohms" specs.http://media.digikey.com/pdf/Data%20Sheets/Yageo%20PDFs/RC0805%20Pb%20Free.pdf (http://media.digikey.com/pdf/Data%20Sheets/Yageo%20PDFs/RC0805%20Pb%20Free.pdf)

Not really an option for the uA range either which uses an 0805 10ohm resistor. So if you lowed the fusible resistor size to 0603 (0402 possibly takes you into different PnP machine territory), then you'd need it to be the same value or more to blow before the precision shunt does. So you've just doubled your burden voltage at least.

So any way with any type of fusing there are trade-offs.There have been very few reports of blown resistors over the years.

I was going to suggest (if it isn't too late for a board rev) having optional mounting pads for SMD fuse holders like Mike suggested (e.g. Littelfuse NANO2).Would be great upgrade that people could do by cutting a couple of (otherwise fusible) traces and mounting these between R1 & SWA-1A, and between R1 & R9.BTW, is R9 connected to the correct terminal of R1? Isn't that putting the uA range through the Kelvin sense terminal?

a fuse makes no sense:1) The ultimate scope of this design is low burden, i.e. now 20mOhm compared to 70 mOhm of the old design.2) R1 does not need a fuse, normally. It is rated for nominal 10A (1W) , 31A max, see Vishay specification. But I estimate, it will desolder itself when > 500mW / > 7A are applied. I doubt that the switch will survive such high currents.

For R1 the connection of R9 makes no difference, because R9 is 1000 times bigger than R1, and the current 1000 times smaller. R9 should have been connected to IN- directly, but the chosen circuitry is easier concerning the switch and more precise.

Normally, R1+R9 = 10.01 Ohm gives an additional 0.1% error for the µA (10.00 Ohm) shunt, but Dave implied a "trick": R2 = 10k is in parallel to the 10.01Ohm, thereby reducing the µA shunt again to exactly 10.00Ohm.

For R1 the connection of R9 makes no difference, because R9 is 1000 times bigger than R1, and the current 1000 times smaller. R9 should have been connected to IN- directly, but the chosen circuitry is easier concerning the switch and more precise.

No, R9 needs to be were it is to compensate for the fixed R2 value in parallel.

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Normally, R1+R9 = 10.01 Ohm gives an additional 0.1% error for the µA (10.00 Ohm) shunt, but Dave implied a trick: R2 is in parallel to the 10.01Ohm, thereby reducing the µA shunt again to exactly 10.00Ohm.

Correct.For switching limitation reasons R2 is always connected, so gives an error of 9.99 miliohms lower than nominal R9 value of 10R on the uA range. But we conveniently have R1 which is 10 miliohms - close enough!, so we put R9 and R1 in series which is then parallel with 10K R2 to give us back our precise 10R uA shunt. And this is done via the sense line, which at uA level makes no difference, but that enables another trick at the same time:In mA mode, R9 is now switched in series with the sense line and opamp, through which no current flows, so no effect.

Correct.For switching limitation reasons R2 is always connected, so gives an error of 9.99 miliohms lower than nominal R9 value of 10R on the uA range. But we conveniently have R1 which is 10 miliohms - close enough!, so we put R9 and R1 in series which is then parallel with 10K R2 to give us back our precise 10R uA shunt. And this is done via the sense line, which at uA level makes no difference, but that enables another trick at the same time:In mA mode, R9 is now switched in series with the sense line and opamp, through which no current flows, so no effect.

I was rather chuffed when I came up with this solution ;D

Well, it's a really nice design. You have really put a lot of "gray cells" into it. Plus some very high-grade components.Before that, I did not even know low Ohm shunts with <1% tolerance.The circuitry is really "precision" grade.

As the worst case specification would be 0.25.. 0.3% + 50µV max. error, will you match the resistors or make a precision testing of the handmade devices?

Dave/Frank - thanks. Yes, clearly a lot of thought has gone into this. I know what it is like working through design tradeoffs. And yes, I did notice the always in circuit R2, and the trick there.Agreed that R1 and R2 would probably be hard to damage in normal use, and looking at the PCB layout, the location of R9 means it isn't at all hard to replace if something stupid ever happens.

It allows you to switch in a short so you can change ranges (break-before-make) without disturbing your circuit. It has been a requested feature.

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Would it not make more sense to have the short in place when in "off" mode (as well)?

Maybe

I can't see a reason to not to have it short when off - if you're using it as a debugging/development aid, a lot of the time you won't be wanting to measure, so want it off to save battery, but don't want the hassle of disconnecting.

I can't see a reason to not to have it short when off - if you're using it as a debugging/development aid, a lot of the time you won't be wanting to measure, so want it off to save battery, but don't want the hassle of disconnecting.

There are probably a lot of good ideas (especially from folks of your pedigree) that could be incorporated into the uCurrent. But at this state in the uCurrent development and the KickStarter campaign, I doubt Dave wants to start re-spinning boards. Plus, there's always the uCurrent BeCu to look forward to.

PS: Just found out, that you were using a CSM2512 metal foil precision shunt, from Vishay Precision. (about 6AU$ @ 1000EA)

Holy crap! I'd hate to be the one that is paying your invoices. Mind if I ask if you ordered all the parts before you did the kickstarter? I thought you were always against taking pre-orders?

Yes, as mentioned in the campaign I bought some of the critical items because I didn't want to get caught short. And I will likely have to buy the rest with my own money as well, because KS take 2 weeks after the campaign to pay, and that sucks.I've been in this kit game a long time, so I know roughly how many of these I can sell, so the risk was small.Yes, I'm usually against pre-orders, but I'm trying out these crowd funding things to see how well they work. I talk about them all the time, and to have no experience with them means I'm just talking out my arse.

Hi Dave. For my own education, how come? Obviously it is from a technical perspective fully compliant (certainly no EMI!), but it used to be all non-purely passive devices (light bulbs) needed approvals. Maybe things have changed. I looked at the ACMA website and I could not find any info in its messed up website. That ACMA needs a new webmaster. It is almost as bad as the Motorola semiconductor website a few years ago.

Hey, I might owe you $2.5K or part thereof... I had lunch with you at the electronics expo in Melbourne about 2 years ago at the tennis centre. But for now I am more than happy to have pledged for a uCurrent (worth every cent!)

Because it would be silly. I'm not going to go waste tens of thousands of dollars getting approvals for every country I have to sell this into. No one else in this game is silly enough to do it, and I'm not either. No one cares.

It allows you to switch in a short so you can change ranges (break-before-make) without disturbing your circuit. It has been a requested feature.

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Would it not make more sense to have the short in place when in "off" mode (as well)?

Maybe

I can't see a reason to not to have it short when off - if you're using it as a debugging/development aid, a lot of the time you won't be wanting to measure, so want it off to save battery, but don't want the hassle of disconnecting.

..or maybe just a less deep case - looks like there's quite a bit of empty space.

Yes, but handy to accommodate bigger battery if desired. 3 x AAA's works well, or maybe 3V lithium.I'm not sure how willing the (Australian) manufacturer would be to do custom stuff.I've asked before for 1000qty to get some holes drilled, or even just provide it without the lid (that's just wasted), but no joy.Black, Grey, translucent blue, and clear are three colour options I can likely get.I've showed the translucent blue before and no on liked it.

That's more than I was expecting, and puts it into a difficult category. I was going to get 1000 made, but if I get closer toward 1000, then I'll have to jump that up to 1250 or maybe 1500 units. Because component volume and pricing works best at that point. And I'll need some for the eventual dealer requests and ongoing post sales.Any need above that gets awkward again in terms of component pricing and reel qty.Also, it's at a point where I can't test or ship them all myself, so I'll now have to set up a decent test system that can be used at the assemblers, and find a way to ship these as well. If it was say 500 units, I would gone bugger it, I'll just do it all myself. But I knew this might happen of course.It's a good thing, right? :-//

This chart keeps track of daily backers:http://www.kicktraq.com/projects/eevblog/current-gold-precision-multimeter-current-adapter/#chart-daily (http://www.kicktraq.com/projects/eevblog/current-gold-precision-multimeter-current-adapter/#chart-daily)It's tapering off, but hard to say what the eventual number will be.I really need to order parts now to ensure I'm not left hanging in the breeze.

Yep, you can pledge any amount without selecting a reward. Either because you pledge less than the lowest reward (not even enough to buy Dave chocolate) or you just don't care about the rewards. This would generally be more common with things like art projects where it's more about the project than about the rewards. Or open-source software projects where the only reward is getting your name in the credits. In this case you might as well donate to Dave via Paypal if you don't want a uCurrent unless you're desperate to troll the KS comments ;).

If you really want a fuse in the current sensing circuit (and worry less about the burden voltage), you could of course use one of those fuse holders that go in your leads.

@Dave: Are there any absolute maximum ratings (non-damaging limit) for the µCurrent Gold? What about the output impedance, I guess you want the impedance of your meter (or other attached device) higher than 100ohm/0.05%=200k? Would be nice if the absolute maximum ratings were included on the spec sheet (http://www.eevblog.com/projects/ucurrent/)

Hi Dave, any chance of a few more Signature Editions? eg: "LATE SIGNATURE EDITION" ? :) I'm kinda late to the party, but would be very happy to upgrade to a higher pledge-point... you've gotta have some other stuff you could throw in along with some signed, hand-assembled uCurrents, to create another pledge level for those of that want to give a bit more money, but that have a lot less money than sense :)

Just to be clear about this 100x voltage mode, is the idea that you use exactly the same input terminals as normal, with the mA, uA, and nA switch effectively acting as an input impedenace selector switch? With most users probably wanting nA (10k input impedance)?

Just to be clear about this 100x voltage mode, is the idea that you use exactly the same input terminals as normal, with the mA, uA, and nA switch effectively acting as an input impedenace selector switch? With most users probably wanting nA (10k input impedance)?

I would guess this one will just get over the $100k mark, and considering that half of that will go as cost of goods and half of the rest as tax it still is a good result.

Yes, people somehow think that 100K is a lot, it's nothing of the sort. KS and the CC merchant take $8K right off the bat, and that's on the gross value, not net profit. What's left after buying all the parts gets taxed 30%. And there are losses in the components based on the reel qty I have to buy at certain price point. Postage isn't cheap and is basically factored in at-cost etc.Take Jeri's CastAR for example. She'll basically be making a loss (or break even if lucky) on that $1M she got. Same with many other KS campaigns.

@Dave: Are there any absolute maximum ratings (non-damaging limit) for the µCurrent Gold? What about the output impedance, I guess you want the impedance of your meter (or other attached device) higher than 100ohm/0.05%=200k? Would be nice if the absolute maximum ratings were included on the spec sheet (http://www.eevblog.com/projects/ucurrent/)

Meter impedance does not really matter, unless you start talking 50 ohms. Exact max value will depend upon the output value and state of the battery ESR.

@Dave: Are there any absolute maximum ratings (non-damaging limit) for the µCurrent Gold?

Meter impedance does not really matter, [...]

How about maximum input currents per range? I did see the 5A and 250mA fuse sub-discussion, but are those the absolute maximum before the input shunts are toasted? I will definitely put a label on mine stating these ratinmgs so I will always be aware of them.

Take Jeri's CastAR for example. She'll basically be making a loss (or break even if lucky) on that $1M she got. Same with many other KS campaigns.

Indeed I think it is really hard for young players ( 8) ) to estimate real cost of a project end-to-end. Afraid of making the project too expensive and as a result making no profit with unforeseen cost. Forgetting about tools, taxes, or postage, consumables, ... If someone like Dave goes through all the effort of eg. making a µCurrent I am absolutely fine with making a bit of profit.

The thing is that unless you are using a constant current supply (rare for a DUT), the current is going to be limited when you change ranges. e.g. if your DUT is drawing say 1A on the mA range and you accidentally switch to the uA range, it's not like the same 1A is going to magically flow through your uA 10ohm shunt resistor. DUT's don't work like that.If you really need to know, it's maybe:

The thing is that unless you are using a constant current supply (rare for a DUT), the current is going to be limited when you change ranges.

Could you explain that a little more please. I don't quite get it. Why would the µCurrent effect the current at all? Isn't it suppose to be transparent? My multimeter doesn't limit the current. Clearly I'm missing something.

The thing is that unless you are using a constant current supply (rare for a DUT), the current is going to be limited when you change ranges.

Could you explain that a little more please. I don't quite get it. Why would the µCurrent effect the current at all? Isn't it suppose to be transparent? My multimeter doesn't limit the current. Clearly I'm missing something.

The internal impedance varies per measurement range of the µCurrent. So if you change ranges, the current will be affected by the internal impedance.

Series resistance, the supply will typically be under 5V, as any higher you will not be worried about burden voltage and will use a regular DMM. Under 5V you want low resistance, so any miss settings will only have 5V at best on them. Often less than 3V where you would use this unit.

Could you explain that a little more please. I don't quite get it. Why would the µCurrent effect the current at all? Isn't it suppose to be transparent? My multimeter doesn't limit the current.

Of course your multimeter can limit the current in the exact same way the uCurrent can, but up to 100 times worse than the uCurrent!Measure 100mA on your mulitmeter and then switch to the uA range and see what happens, your product will almost certainly stop working.That's because your multimeter has different current shunt resistors based on the range, just like the uCurrent.

Is there not a minimum value before they apply duty? In the UK you don't pay Customs Duty until the value of the imported items hits £135; you just have to pay VAT on any item over £15.

Annoyingly HMRC don't make the Customs Tariff available for free; you have to buy a subscription to it to find out how much duty they're likely to charge you...assuming you can even figure out what commodity code it's likely to come under (that information is free...but vaguely bewildering).

Annoyingly HMRC don't make the Customs Tariff available for free; you have to buy a subscription to it to find out how much duty they're likely to charge you...assuming you can even figure out what commodity code it's likely to come under (that information is free...but vaguely bewildering).

But the TARIC DB does include the tariffs. And since the UK is part of the EU's custom unit, HMRC (are they still called this?) should be bound by it.

My guess for the uCurrent would be goods nomenclature code 9030 33 10 90 http://ec.europa.eu/taxation_customs/dds2/taric/measures.jsp?Taric=9030331090 (http://ec.europa.eu/taxation_customs/dds2/taric/measures.jsp?Taric=9030331090) I.e, for import from some countries 0%, for others 4.2%.

My guess for the uCurrent would be goods nomenclature code 9030 33 10 90 http://ec.europa.eu/taxation_customs/dds2/taric/measures.jsp?Taric=9030331090 (http://ec.europa.eu/taxation_customs/dds2/taric/measures.jsp?Taric=9030331090) I.e, for import from some countries 0%, for others 4.2%.

Oh, helpful. I think it would be 4.2%. The 0% tariffs are mostly for EEA countries and countries the EU gives preferential treatment to (I think that's mostly less developed ex-European colony countries).

And they're still HMRC - that was their new name after HMCE merged with Inland Revenue. I suspect the main reason for merging them was so that they could use HMCE's somewhat extensive powers.

the best thing (for EU people) would be doing like I suggested in my previous message:http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg349792/#msg349792 (http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg349792/#msg349792)

Annoyingly HMRC don't make the Customs Tariff available for free; you have to buy a subscription to it to find out how much duty they're likely to charge you...assuming you can even figure out what commodity code it's likely to come under (that information is free...but vaguely bewildering).

In addition to Bored's link, there's also https://www.gov.uk/trade-tariff (https://www.gov.uk/trade-tariff) which lets you browse the tariff for free; there is a note pointing out that it might be at variance with the subscription version in which case the latter is correct, but it's good enough to avoid surprises in my experience.

Annoyingly HMRC don't make the Customs Tariff available for free; you have to buy a subscription to it to find out how much duty they're likely to charge you...assuming you can even figure out what commodity code it's likely to come under (that information is free...but vaguely bewildering).

In addition to Bored's link, there's also https://www.gov.uk/trade-tariff (https://www.gov.uk/trade-tariff) which lets you browse the tariff for free; there is a note pointing out that it might be at variance with the subscription version in which case the latter is correct, but it's good enough to avoid surprises in my experience.

Added to my bookmarks; cheers for that. Once upon a time I could find things on the gov.uk site, back when it was open.gov.uk...

the best thing (for EU people) would be doing like I suggested in my previous message:http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg349792/#msg349792 (http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg349792/#msg349792)

Annoyingly HMRC don't make the Customs Tariff available for free; you have to buy a subscription to it to find out how much duty they're likely to charge you...assuming you can even figure out what commodity code it's likely to come under (that information is free...but vaguely bewildering).

In addition to Bored's link, there's also https://www.gov.uk/trade-tariff (https://www.gov.uk/trade-tariff) which lets you browse the tariff for free; there is a note pointing out that it might be at variance with the subscription version in which case the latter is correct, but it's good enough to avoid surprises in my experience.

I don't think there's any way around the VAT issue. It's pretty watertight if you are importing with correct paperwork. Importer will pay VAT and customs to the shipper at point of entry, if you havea VAT number you can claim it back. However if you then want to resell inside the EU you have to charge VAT yourself (unless the end buyer has a EU VAT number).So in short, if you have an employer or friend who is VAT registered ask them to get if for you.

I don't think there's any way around the VAT issue. It's pretty watertight if you are importing with correct paperwork. Importer will pay VAT and customs to the shipper at point of entry, if you havea VAT number you can claim it back. However if you then want to resell inside the EU you have to charge VAT yourself (unless the end buyer has a EU VAT number).So in short, if you have an employer or friend who is VAT registered ask them to get if for you.Custom duties, everyone pays. No refunds!

I was not talking about evading VAT, but a BULK direct import to Europe of maybe 2-3 hundreds of µCurrent units and a reshipping from inside EU will save lots of importing duties/shipping costs/...Even VAT is not equal in every EU state: here in Italy is 22%, instead in UK is 20% (I payed less my Flir E4 buying it from Omega because they were shipping from the UK: 800€+15€shipping+20%VAT=978€ total!). So several times here in Italy it can be cheaper buying abroad even if the shipping expenses are higher.Those savings can be used to cover the costs an individual will occur: just as an example here in Italy I pay taxes and duties on the TOTAL amount (s/h included) I paid, not only on the simple value of the goods.Taxes and duties also depend on how the inspector has awakened in the morning: once for the same two parcels (different addressee) shipped to the same city (Udine) and arrived the same day at customs, the difference of duties was of 10€ on the total amount to be paid (unfortunately it was me the unlucky one!). I raised an official complain regarding this different treatment but the answer I got was of typical Italian bureaucracy: incomprehensible and no explanation at all on why they have done so. :( So, I really do not want to evade VAT, but I'd like to pay the right amount of duties.

I'm not sure if it would make a big saving. The S&H costs are fairly reasonable, I dont know what other EU countries costs are but I'd say to post a uCurrent well packaged from EU to EU is going to cost not much less than what Dave is.

Also the distributor will want 30% minimum markup. Any savings and discounts will get eaten fairly quick.

Please can you explain how I will be able (with smoothieboard) to not pay import duties and the shipping supplement as in the original offer (+15USD to cover s/h to Europe)?If they were able to do it, I think there are some provisions to do it for the µCurrent GOLD too!!!

Please can you explain how I will be able (with smoothieboard) to not pay import duties and the shipping supplement as in the original offer (+15USD to cover s/h to Europe)?If they were able to do it, I think there are some provisions to do it for the µCurrent GOLD too!!!

Smothieboard is open hardware, just like the µCurrent, so anyone can make one - the Eagle files are available for download. What you can additionally do is is ask for permission to manufacture and sell them under the Smoothieboard name, which is what Ipso Factio have done for the EU market.

Dave could theoretically do the same thing, however that adds additional overhead for Dave because he'd now also need to keep an eye on the manufacturing quality of other people making µCurrent boards, to ensure they matched his standards; any duff manufacturing by a third party is going to reflect on him. Although I suspect there are EU based people he'd trust do it - it's whether it's worth their while as well.

***

Actually I've just noticed he does do this, µCurrent is available from http://www.robot-italy.com/en/ucurrent-pre-built-tested.html (http://www.robot-italy.com/en/ucurrent-pre-built-tested.html) - possibly µCurrent Gold will be too...

Smothieboard is open hardware, just like the µCurrent, so anyone can make one - the Eagle files are available for download. What you can additionally do is is ask for permission to manufacture and sell them under the Smoothieboard name, which is what Ipso Factio have done for the EU market.

Sorry to correct you, but the board (to my knowledge) is being produced only in the USA and will be bulk shipped and imported in EU. Costs will be reduced (only one shipping and import) and the savings will full cover for the shipping(from USA)/importing (to EU)/reshipping (to EU customers)/VAT expenses.

but why is there still no soft latching power-on circuit in these uCurrents? because that tiny battery drains out if the device was left on overnight (happened to me twice).I always forget my Fluke started but I really care less, since it will go into standby after a few minutes. It would be nice if the uCurrent would do the same.

Because it would need to sense the output voltage and reset the timer. Not a trivial amount of circuitry to add to essentially a single sided SMD layout.If you are concerned about battery life, you can use 3xAAA's or a CR123 battery for greatly increased life.

Because it would need to sense the output voltage and reset the timer. Not a trivial amount of circuitry to add to essentially a single sided SMD layout.If you are concerned about battery life, you can use 3xAAA's or a CR123 battery for greatly increased life.

I see what you mean. would it be too late to add to your pcb something like an unpopulated MOLEX 0532610471 pad? there would be no need to change the stencils.this connector would have +BT1, -V, VGND and VOUT signals in any order. this would allow an easy way to mod your device.

I intend to do a small open-hardware msp430 based project that would control the power delivery to the uCurrent.

later edit:I put together a github repo with my initial thoughts. it is available here: https://github.com/rodan/ucurrent_ctrl

but why is there still no soft latching power-on circuit in these uCurrents? because that tiny battery drains out if the device was left on overnight (happened to me twice).I always forget my Fluke started but I really care less, since it will go into standby after a few minutes. It would be nice if the uCurrent would do the same.

Because it would need to sense the output voltage and reset the timer. Not a trivial amount of circuitry to add to essentially a single sided SMD layout.If you are concerned about battery life, you can use 3xAAA's or a CR123 battery for greatly increased life.

Actually pretty trivial - a 6-pin PIC and maybe something to switch the power (may be possible to power everything off an I/O pin). You'd probably save the cost by not needing the battery voltage monitor, and could add an overrange indicator by flashing the LED. e.g. PIC10LF320 SOT-23-6 US$0.36 including factory programming, ink-dot marking and re-reeling. You could even save the cost of an on/off switch by using a touch button.

Hi Dave, any chance of a few more Signature Editions? eg: "LATE SIGNATURE EDITION" ? :) I'm kinda late to the party, but would be very happy to upgrade to a higher pledge-point... you've gotta have some other stuff you could throw in along with some signed, hand-assembled uCurrents, to create another pledge level for those of that want to give a bit more money, but that have a lot less money than sense :)

Cheers!

Drat. Missed 'em again (announced at 4:50am local time). Oh well :/ Glad the campaign went well (gangbusters?) for you.

Can't you just stop the campaign at a certain number? If you want to avoid buying another reel of parts for just a few needed.I heard you talking about the "pit of despair" on the Amp-hour and surely you are standing precipitously on the edge now at 974. I am assuming that 1000 is the reorder point for a new reel.

Yes, but I need to manufacture more anyway for further sales through the dealers.

Hi Dave!,Just saw the reflow of the green PCB; looks good. You said the they are going to send you some new ones with better silkscreen. So I asked before, and I'll ask again, how do I get a green one? ;D

and you said something about :box: day; had to look that one up. Dec. 26th

Hi Dave!,Just saw the reflow of the green PCB; looks good. You said the they are going to send you some new ones with better silkscreen. So I asked before, and I'll ask again, how do I get a green one? ;D

I'll probably assemble them all and make them available after the campaign. Probably too late to include in the campaign now as another perk.

:clap: Backed and best of luck Dave with making the 1000+ units hope it goes smoothly. :-+Love the look of the green ones i mite down load the pcb files and get one made with the next batch of boards.Was it just the Precision resistors that are hard to get?

The precision resistors, the switch, and the Maxim chip.I think I've bought out the worlds supply of switches ;DMostly all sorted now. Vishay are going to help me get the resistors in shorter time.They have also sent me some nice precision samples which I'll do a short video on.

The precision resistors, the switch, and the Maxim chip.I think I've bought out the worlds supply of switches ;DMostly all sorted now. Vishay are going to help me get the resistors in shorter time.They have also sent me some nice precision samples which I'll do a short video on.

The worst thing is discontinued parts we had a new control board prototyped and ready for production. |OLucky I checked the availability of all the parts.It was a little SOIC package high side mosfet driver from International Rectifier.We only needed 100 off and could not find stock anywhere not even anything pin compatible. :-//A last minute change to a microchip TC4431EOA.Not tested or prototyped we just got one in over night and point to point wired it and sent the new board files off for the production run. :scared:all worked in the end. :-+

Look forward to your video on precision resistors.PS could you post some High Res images of a EEV and Amp Hour poster would love to put them on display at tafe and work.

About the "First Manufacture" video.I assume I see 1V/1mA test that should have a spec of 0.1% (improved from 0.5%)But your Agilent limits are set less strict, 0.1% is between 0.999 and 1.001 volt, 0.998 should show a red background? seems more like it is set to check within 0.25%

in your latest video "uCurrent... First Manufacture" , you stated to test or to guarantee half of the specified limits.

But you specify a typical error of 0.05% / 0.1% only, not worst case, which would be 0.25% for nA and µA ranges, and 0.3% for mA range, due to error propagation of the 5 different resistors (trimming tolerance errors only) involved in the measurement chain.

The probable error (due to error cancellation) might be 5 * 0.05% / sqrt(5) ~ 0.1%, but still 4 times higher than the 0.025% you claim to test.

So my question is, how you will set the pass/fail parameters in your series production?And how will you treat units which lie outside limits?

It would also be very interesting, if you later publish details about the setup of the test equipment for the series production run, and the yield of the production run.

KickStarter still requires you to create an account and provide them your credit information and your personal billing information which just infuriates me. However, my desire for one of Dave's Gold uCurrents has won out over my continued frustration with companies wanting to service me better.

It was not that I couldn't pledge with a Credit card, it would just have been much easier and accommodating if PayPal was accepted or if an alternative method of 'donation' to Dave or EEVBlog for the appropriate amount could have been considered.

Ha! I was reading some of the recent comments on the indiegogo $9 arduino (a successful campaign - something like 15k sold). But there was a few lost in shipping, a few (still) stuck in customs, and some that got delivered to the wrong address. Stuff like that happens.

For the (small percentage of) people that didn't get theirs promptly, or had theirs (still) stuck in customs, they sure do raise a ruckus.

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Merry Fu****g Christmas Harold hope your happy with the number of people still waiting your a useless c**nt how many people are without gifts due to YOU??

Your µCurrent GOLD sounds like a very useful adapter, unfortunately I don't have enough "GOLD" to buy one as I'm disabled and basically homeless. While I don't do much electronics work, a lot of what I do is guess work and surprisingly I get stuff fixed most of the time when people are willing to pay for parts (I wish some of those people had been willing to pay me too).

Your rulers also look very useful but again I've no money. Not that I can even find a place to buy them.

Also I just registered (or re-registered, I thought I had registered before but maybe I got dropped for inactivity since this is the first chance I've had to write, I don't have much time online since I don't have my own connection and I'm terrible at writing) and I'm curious what would've happened if I chose anything other than yes on the "Are You Human?" question. :P

Based on Dave's post, I increased my kickstarted funding for 2 units. I hope this quantity (2 units) will be recognized by the level of my funding as I did not find a specific way to specify that I wanted two uCurrent Gold and not just one. Kickstarter appears to be setup for single units only. I am eagerly awaiting delivery! A big thanks to Dave for his many postings on how the project is progressing.

It allows you to switch in a short so you can change ranges (break-before-make) without disturbing your circuit. It has been a requested feature.

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Would it not make more sense to have the short in place when in "off" mode (as well)?

Maybe

I can't see a reason to not to have it short when off - if you're using it as a debugging/development aid, a lot of the time you won't be wanting to measure, so want it off to save battery, but don't want the hassle of disconnecting.

Looking at the schematichttp://www.eevblog.com/files/uCurrentRev5schematic.pdf (http://www.eevblog.com/files/uCurrentRev5schematic.pdf)I think if you want a short while off, you just have to add two jumpers on SW2. One from pin 1B to 4B and another from pin 2B to 3B.

Another thing you could do instead is cut the trace to isolate SW2 pin 1A. Then you would have Off (with burden resistance) - On - Off-short. I don't really see a need for On-short.

Does anyone think an asymmetrical virtual ground would be a good idea?

I'd like to be able to take full advantage of the 2V range of my meter and I rarely want to measure positive to negative current swings. The virtual ground could be shifted downwards to change the ranges from +/-1250xA to between +2000xA and -500xA. Reversing the leads would allow -2000xA to +500xA readings (with equipment ground considerations).

My brain may not be functioning at 100% after last night's New Year's celebrations ;) but I believe that if you wanted to have the same current through the divider, changing R6 to 158k and R7 to 39.2k should accomplish this.

I just had a huge WTF moment opening the Altium files, Dave.You did not give use component numbers, nor BOM. It is not like I want to build one myself, you know it is not economical, I'm just curious. You wrote open hardware there, give us all the information required to make it. Even you said this some 500 videos before.Several files are "not found" when opening the project.There is total of 240 DRC errors on the design.You used a 1206 footprint for the 0805 LED.Did not include the Library for the project.You use mils and american symbols on the schematic

I just had a huge WTF moment opening the Altium files, Dave.You did not give use component numbers, nor BOM. It is not like I want to build one myself, you know it is not economical, I'm just curious. You wrote open hardware there, give us all the information required to make it. Even you said this some 500 videos before.Several files are "not found" when opening the project.There is total of 240 DRC errors on the design.You used a 1206 footprint for the 0805 LED.Did not include the Library for the project.You use mils and american symbols on the schematic

I have not got around to releasing all the info yet.I don't do project based libraries. You can generate it yourself from within Altium.

Thanks for the plug (no pun intended :))! Yes, I sourced those for Dave and I do have some in stock but I haven't had time to list them in my eBay store yet. Please contact me privately if anyone's interested in getting some.

Regardless of inherent protection due to increased shunt resistance when switching ranges, and other factors, I'd still like to know what the maximum continuously sustainable safe current would be for each range based on:

- Not exceeding the continuous safe wattage of the shunt resistors

and/or

- Not frying any of the circuitry due to the voltage impressed upon the shunt resistors from the current flow.

This would be for both the µCurrent powered on and off, if it makes a difference.

The questionaire that you sent out for the uCurrents didn't ask if we wanted the cases signed; I assume that you will be signing them all? If not, I would like mine signed :) (since I don't know when I will be able to get out to Australia to try and get my Fluke 27 signed ;) )

The questionaire that you sent out for the uCurrents didn't ask if we wanted the cases signed; I assume that you will be signing them all? If not, I would like mine signed :) (since I don't know when I will be able to get out to Australia to try and get my Fluke 27 signed ;) )

Yes, all will be signed.First units shipped today!I wonder if any other hardware kickstarter has shipped on the same day as the money came through?

u271D, from the emails I got we will have to wait unit they are just about to be posted as Dave only gets one go at getting the addresses for the group, I think we will get surveyed late Jan early Feb if you are the 200 or so group, We will have to wait!

Yes one of the 200, I didn't know he could select what people he was sending the survey to. I did remembered that he only had one shot at it; that's why I posted. I thought all the surveys went at once.

Yes one of the 200, I didn't know he could select what people he was sending the survey to. I did remembered that he only had one shot at it; that's why I posted. I thought all the surveys went at once.

Yes, I can chose the groups. Kickstarter is actually quite nice at this survey thing, it works well. Too bad you can only do it once. The export function works perfectly. About the only thing I'm quite happy with with KS so far.

gdewitte,If you put it on the nA scale, it essentially is a 100X voltage amplifier with a 10k ohm input resistance. If that resistance is too low for you, you would have to remove the 10k shunt resistor.

Note that the maximum usable input voltage would be +/- 12.5mV, for which you would get a 1.25V output. Also note that if you want to get this full output swing even when the battery voltage starts to drop, your output load impedance should be quite high (100k ohm or more, which is true for current measurements as well).

Personally, I think you should not go near any mailing house again. Get a decent label printer like the Zebra brand, and choose the option of friends and family to prepare the shipments. You can ship them out in batches. You would not only save yourself a lot of headaches, but also some serious money.

Did you have to promise/prove some level of volume to get those rates?

Yes, a yearly number.So if I do end up going with a mailing house and I don't meet those numbers, I have no idea what happens if I don't meet it in a years time.They also force you into a credit account which I didn't want, so they had to check my financials and trade references. Which is stupid, because in today's ecommerce world you can run a multi-million dollar turnover business and not have a single trade reference.

What a cool product! Unfortunately, I missed the Kickstarter campaign. I really want the uCurrent Gold, so I was really excited when I found the entire Altium project on EEVblog. I am planning on spinning a few of my own boards and hand populating them. I love open hardware! Thanks for sharing Mr. Jones. Has anyone found a BOM or parts list for the uCurrent Gold? Is there any way that it could be made available? I am not able gather all of the manufacturer part numbers from the schematic, and I want to be sure to get the right parts.

I am not able gather all of the manufacturer part numbers from the schematic, and I want to be sure to get the right parts.

Good luck with that. Dave bought out the entire world supply on various of these components (see the latest video). You'll have to wait or find replacements. As to a parts-list: Earlier in the thread, Dave said he didn't have time to update the uCurrent's files.

Based off the BOM from the last video and current distributor prices, 2000 assemblies looks like around 40,000 USD total parts cost. Nice.How much is your assembly house charging you per board to stuff them? Are they going to do selective solder for the through hole parts?

Note that the description for the LED in the BOM says it's orange but both Digi-Key and the datasheet for the part say it's yellow.Also, why is the Supplier 1 Part # for the LED in the BOM in blue and underlined?

Note that the description for the LED in the BOM says it's orange but both Digi-Key and the datasheet for the part say it's yellow.Also, why is the Supplier 1 Part # for the LED in the BOM in blue and underlined?

Can you not just pick any colour LED if you are going to make this yourself ? Bearing in mind that the high intensity LED's will draw more current from the battery

Can you not just pick any colour LED if you are going to make this yourself ? Bearing in mind that the high intensity LED's will draw more current from the battery

Sorry, I was just pointing out an error that Dave may have missed in the BOM. (The currently posted schematic shows it as green). I guess I came off as being a bit nit-picky. :-[

The intensity of the LED doesn't affect the current draw. It's a function of the LED's forward voltage, the battery voltage, the voltage drop of the ouput driver, and the value of the resistor. Actually, a high intensity LED would require less current, for the same brightness, than a less efficient one.

Can you not just pick any colour LED if you are going to make this yourself ? Bearing in mind that the high intensity LED's will draw more current from the battery

Sorry, I was just pointing out an error that Dave may have missed in the BOM. (The currently posted schematic shows it as green). I guess I came off as being a bit nit-picky. :-[

The intensity of the LED doesn't affect the current draw. It's a function of the LED's forward voltage, the battery voltage, the voltage drop of the ouput driver, and the value of the resistor. Actually, a high intensity LED would require less current, for the same brightness, than a less efficient one.

yes I agree, I was referring to the optimum rating so a 20mA Red led would use less then a 50mA High intensity if driven at full brightness, if you were derating the high intensity then yes it would use less power

Regardless of inherent protection due to increased shunt resistance when switching ranges, and other factors, I'd still like to know what the maximum continuously sustainable safe current would be for each range [...]

Since nobody has replied about this and the BOM is now available, so we can get information for all the components, I'll take a stab at this myself. This will be a very conservative estimate based on the information available in the datasheets.

I'll assume that the worst-case scenario is with the power off. The shunts will still be connected across the current input terminals J1 and J2, and feed into the inputs of U1. None of the datasheets for the active components give internal schematics, so I'll assume that:

+V and -V will be held to the same voltage level through a reasonably low impedance (at least via the 200K of R6 and R7).

The inputs of U1 will have a very high impedance even with no power on the chip, at least within our safe operating range.

There will be a reasonably low impedance path between VGND and either +V or -V. Therefore, the - input of U1 will couple through R5 to VGND (and thus +V and -V), so will not be a factor. I can't be sure of this without internal schematics but it's the safest assumption.

Current through the shunts will impress a voltage upon the + input of U1 via SW1. The + input is high impedance, so the voltage on it will be equal to the voltage across the shunt resistor(s) selected by SW1. The only absolute maximum rating given for U1's + input is "(-V - 0.3V) to (+V + 0.3V)". I'll assume this is even with no power on the chip. No information is given on what amount of current or power is safe if we exceed these voltages, so we can't exceed 0.3V across the shunt resistors(s), with current flowing in either direction. To be safe we should probably lower this to 0.28V.

The other limits we have are the power ratings of the shunts and the current ratings of SW1's contacts.

For the mA range:The shunt is 0.01ohm R1. SW1's contacts are rated 4A at 28V DC and no other higher currents are specified for other voltages, so we have to make 4A our maximum. R1 is rated 1W at ambient temperatures up to 70C. At 4A, R1 will draw 0.16W, so it's safe. At 4A, R1 will be at 0.04V, so U1 is safe.

For the uA range:The shunt is formed by a series-parallel arrangement of R9, R1 and R2 but R1 and R2 are insignificant for these calculations, so we can just consider 10ohm R9 to be alone. The safe voltage of 0.28V across R9 will require 0.028A. R9 is rated 0.1W at ambient temperatures up to 70C. At 0.28V, R9 will draw 0.00784W, so it's safe. SW1 obviously is safe.

For the nA range:The shunt for this range is 10Kohm R2. The safe voltage of 0.28V across R2 will require 0.000028A. R2 is rated 0.063W at ambient temperatures up to 85C. At 0.28V, R2 will draw 0.00000784W, so it's really safe (as SW1 still is).

Summary:

For the mA range, the maximum safe continuous current is 4A, which is 3.2 times the 1250mA full scale value.

For the uA range, the maximum safe continuous current is 28mA, which is 22.4 times the 1250uA full scale value.

For the uA range, the maximum safe continuous current is 28uA, which is 22.4 times the 1250pA full scale value.

Since nobody has replied about this and the BOM is now available, so we can get information for all the components, I'll take a stab at this myself.

Thinking about my previous post a little further...You could add some protection for U1's inputs when the power is off, without affecting the powered on circuit in any way. With power on, and providing that the battery good indicator is lit, the maximum allowed voltage on the inputs would be about 1.6V instead of 0.28V. I'd make it 1.5V just to be safe.

The mA range would still be limited by the switch contacts, so would remain at maximum 4A.

The uA range would now be limited by the power that the shunt can safely handle. R9 is rated 0.1W but to be safe I'd derate this to at most 75% (0.075W). At 0.085A R9 would draw about 0.072W and the voltage would be 0.85V, which is safe for the input.So the maximum safe current on the uA range would now be 85mA instead of 28mA.

The nA range would still be limited by the input voltage. For 1.5V this would be 0.00015A at a very safe 0.000225W.So the maximum safe current on the nA range would now be 150uA instead of 28uA.

Protection could simply be accomplished by switching a short across the current inputs when the power is off. However, in some cases it might be desirable for the shunt resistance to remain the same for both on and off conditions. This could be accomplished (for currents in a readable range, at least) by putting two schottky diodes back to back across the inputs. These would not conduct significantly at the 12.5mV required for full scale but would clamp at about 0.3V to protect the op amp input.

To modify the uCurrent, all that's required is to jumper pins 2B and 3B of SW2 and put the diodes (or a short) across pins 1B and 4B of SW2. If you wanted the diodes to benefit from whatever protection is offered by the PCB trace fuse, you would wire the diodes between SW2 pin 4B and the big PCB trace between the trace fuse and R1 (after scraping off some solder mask).

Christopher, right now the best option might be to take Dave's schematic and make one of your own. In a few weeks I bet we'll hear of some overrun for sale but that's pure speculation. Here's hoping Dave's assembly house pulls a few ghost shifts...

#22 arrived in Santa Cruz today. Cheers Dave! Happy to see the battery installed and ready to go but first ima eat this fudge.

Alas, the battery powered scale project that I ordered it for was canceled this week. Now I need to find something else to use it on...

Just a sanity check. I am assuming the "polling" on KS for the shipping addresses for the main batch (i.e., after the initial 200 units or so) has *not* happended yet. Is that right? I have not seen anything yet. I have been charged for my unit, and I am content to wait patiently, but just want to make sure I didn't miss it. Thanks.

Just a sanity check. I am assuming the "polling" on KS for the shipping addresses for the main batch (i.e., after the initial 200 units or so) has *not* happended yet. Is that right? I have not seen anything yet. I have been charged for my unit, and I am content to wait patiently, but just want to make sure I didn't miss it. Thanks.

- Bob, KY3R

Funny you should ask. About 1 hour after you posted this, I got the survey from Kickstarter.

I got the "POLL" email monday I believe and I was in the first 200 batch. So far so good. :-+

Me too. In retrospect I shouldn't have used all those special German letters in my address (like "ß" and "ü"). Hope it's not going to be a problem. They're just contractions and can easily be replaced by "ss" and "ue".

Suggestion for Dave, if possible, you can make similar video too with µCurrent in production.

How it's made - Ladyada and Micah Scott manufacturing Fadecandy at Adafruit (http://www.youtube.com/watch?v=UvWWITJn5UU#ws)

It could be interesting, since very few of hobbyists has ever see those machinery in action, and regardless that there is a ton of similar videos on YouTube, it could be interesting to see your own board birth.

Sounds like the kind of unreflected over reaction legislators have, every time a statistically inevitable mishap happens:

"Boohoo, we've shipped a bazillion Li-Ion batteries. Now after 30 years one has exploded. It was defective to begin with. Never mind the bazillion that didn't. Ban them! BAN THEM ALL!!! ...NOW!!!" :palm:

Sounds like the kind of unreflected over reaction legislators have, every time a statistically inevitable mishap happens:"Boohoo, we've shipped a bazillion Li-Ion batteries. Now after 30 years one has exploded. It was defective to begin with. Never mind the bazillion that didn't. Ban them! BAN THEM ALL!!! ...NOW!!!" :palm:

and they don't even take into account energy density. So a CR1616 battery is just as illegal and deemed to be the same risk as a 1000Wh ultra high high current pack.

Anything with any form of lithium battery, no matter how low energy, is not allowed to go by Australia Post airmail within or outside the country.It's the law for a "general carrier" like them.

Same true of U.S. Postal Service. In fact, every time I go to the post office to send a package, the agent robotically rattles off this rote formula asking whether my package has any hazardous materials. At the end of the litany is "... lithium batteries or perfume." Okay, while I understand the potential issue with lithium batteries--in theory, at least, although as a practical matter it is regulatory overkill--what's the deal with perfume?!

More the fact that most perfume is in glass fragile bottles that may explode in unpressurised cargo. They also frown on spray cans these days. Flammable vapour and an ignition source like a platinum ring in another envelope or a nickel catalyst like stainless steel will possibly result in a fire if the conditions are exactly right and you have enough heat from another source to start the reaction.

Dave,In your recent Kickstarter update #17 video, at approx. 0:34, you mention that the board at position 6 (S/N 202) had "failed the spec on one of the ranges". Just out of curiosity, I'd be interested in knowing what the problem turned out to be.

Also, what percentage of boards have had problems, so far. Have there been just a few identical problems or random issues?

In your recent Kickstarter update #17 video, at approx. 0:34, you mention that the board at position 6 (S/N 202) had "failed the spec on one of the ranges". Just out of curiosity, I'd be interested in knowing what the problem turned out to be.

In theory a board may not pass spec due to accumulative component errors. I test to a tighter spec than the worst case error margin. So I expect some failures here.

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Also, what percentage of boards have had problems, so far. Have there been just a few identical problems or random issues?

A few solder bridges on some re-hand soldered parts that got rotated incorrectly on the machine setup, no big deal, and fixed for the next run.Have not tested them all yet though.

Strange that the battery can't be included. Is this some AU regulation?

Anything with any form of lithium battery, no matter how low energy, is not allowed to go by Australia Post airmail within or outside the country.It's the law for a "general carrier" like them.

Same law here in the states, however many people ignore it. Generally it only applies to bulk batteries though and most lithium batteries say somewhere on the box "Not for transport aboard passenger aircraft" as well.

One uCurrent received in Denmark. On the back of the envelop the date says 25/2

Thanks, yes, shipped on the 25th, and yours was the first international batch to ship, so looks like it takes at least 7 days. No real difference from the usual International airmail. It used to be quicker pre Sept 11th.

#00118 arrived in Hong Kong! Probably would have arrived sooner if the package wasn't opened and examined by our customs (no fees/tax as HK is tax free for importing pretty much everything). Thanks Dave!

S/N #108 made it to the Netherlands today. Thanks for banana plugs and the extra battery holder! That means I can use three AAA batteries, which also means a supply voltage of 4.5V. That shouldn't be a problem right? :D

That means I can use three AAA batteries, which also means a supply voltage of 4.5V. That shouldn't be a problem right? :D

At 4.5V the Batt OK LED current will exceed the maximum specifications of the TPS3809 voltage supervisor IC.See this thread:http://www.eevblog.com/forum/oshw/current-gold-hw-design-question/msg393341/#msg393341 (http://www.eevblog.com/forum/oshw/current-gold-hw-design-question/msg393341/#msg393341)

That means I can use three AAA batteries, which also means a supply voltage of 4.5V. That shouldn't be a problem right? :D

At 4.5V the Batt OK LED current will exceed the maximum specifications of the TPS3809 voltage supervisor IC.See this thread:http://www.eevblog.com/forum/oshw/current-gold-hw-design-question/msg393341/#msg393341 (http://www.eevblog.com/forum/oshw/current-gold-hw-design-question/msg393341/#msg393341)

Having some sort of user manual would be nice to have then. Things like this could be pointed out in it :) Luckily I decided to power it with a coin cell.

That's puzzling. The ID Recorded sticker is required for international mail items when you send them at the post office as Joe Public (you need to show photo ID for all international shipments), but I deliberately went through a verification test to get signed up to be an approved international shipper (RIC), and as such I don't show ID when I drop this stuff at the business hub depot.

this kickstarter plaftorm is remarkable. i saw what it can do up and close with a small startup called pressy that have designed this gadget that inserts into headphone jack on an iphone. great idea. anybody else in on this invention? im looking for garage type innovators like these guys to work in a collaborative project. others who want to get in on the ground floor so to speak.

That's puzzling. The ID Recorded sticker is required for international mail items when you send them at the post office as Joe Public (you need to show photo ID for all international shipments), but I deliberately went through a verification test to get signed up to be an approved international shipper (RIC), and as such I don't show ID when I drop this stuff at the business hub depot.

mine had the sticker too, seems like they are wasting time and stickers then! I guess though it's not costing or affecting you in anyway?

surprised by the photo id requirement though, seems a bit OTT!

No requirement like that here, if it has the right postage you dont even need to take it to the post office counter.

Between 00062 and 00097 they probably met the cost of their lunch and decided to be magnanimous from then on. Or got bored.

Or maybe they have my card marked: I did actually attempt to get the police involved with one shipment (deliberately delaying the post is a criminal offence, and they can't hold it in lieu of their fees), but it was just my luck that a local policeman had shot his family that day so they weren't really concentrating on my problem.

Dave,Any guess on when the next batch of 400 will get shipped--and the next 1,000 after that?

I'm about to check with my assembler again.Last I heard they had 400 assembled, more ready to be loaded, and had just got my test jigs and procedures.So I'd certainly be expecting the 400 this week (which I can start shipping same day I get them, some not all, I can't do 400/day), but will have to confirm.

I successfully entered the adress-survey the first time, and now twice again from 2 different browsers. With confirmation emails to back it up. If you still don't have my details then there must be a bug in Kickstarter's system that provides this to you. (emailadress starts with ricojansen, pm if needed fully )

Just got the confirmation email from Kickstarter with address included. So if you do not get one you need to go to the site and check the address is entered, or Dave will just not post one to you, and as there is no way to find you ( the elves did not work, and Dave does not believe in little flying things with halos) you will have made a donation and will get nothing. Not magic, check your junk mail, and fill out the simple survey. 24 updates and counting, I think Dave has met his side of the deal.

I filled my address questionnaire couple weeks ago and with Dave mentioning couple times he would send this questionnaire only shortly before mailing the µCurrent GOLD, I was expecting the device in the mail over the past couple of days. I was getting a bit worried already with all the proud posts in this thread, but this morning I received a "Shipping soon!" message and now I understand I don't have to worry (or at least not yet).

Anyways I was getting a bit confused and worried about delivery, so my feedback for today (probably mentioned before somewhere in the previous 28 pages of posts ...) is: Check if you received the "Shipping soon!" message before getting worried.

Anyways I was getting a bit confused and worried about delivery, so my feedback for today (probably mentioned before somewhere in the previous 28 pages of posts ...) is: Check if you received the "Shipping soon!" message before getting worried.

I had quite a few of these emails and messages fro the $79 backers asking where it is. I thought I was pretty clear in the updates that only the $85 ones had shipped so far?The $79 backers will start shipping tomorrow, Sagan and SWMBO have been employed as labels stickers and couriers :-+Oz ones will go first, followed by international in backer number order.At this stage I can't say when they will all ship, as boards are still rolling in from the assemblers and I can't really physically ship more than a few hundred a day.

Just got the confirmation email from Kickstarter with address included. So if you do not get one you need to go to the site and check the address is entered, or Dave will just not post one to you, and as there is no way to find you ( the elves did not work, and Dave does not believe in little flying things with halos) you will have made a donation and will get nothing. Not magic, check your junk mail, and fill out the simple survey. 24 updates and counting, I think Dave has met his side of the deal.

I did already, and filled in appropriately on the Feb 25th. But when I received the KS update #23 I wasn't sure if it was selectively mailed to those that Dave didn't have the adress-details of, or if it was a general broadcast update to all backers. When I got update #24 the other day I got worried. But I guess all is good now, I got the "Shipping soon" message within a few hours later.

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There is a local saying here - Kry you Gat in Rat Vaalseun!

Since Afrikaans is phonetically much like Dutch, I am curious what you mean by that. "I get a hole in what kind of rodent?" ???

(maybe a response by PM if it goes too much off-topic from this subject)

Anyways I was getting a bit confused and worried about delivery, so my feedback for today (probably mentioned before somewhere in the previous 28 pages of posts ...) is: Check if you received the "Shipping soon!" message before getting worried.

I had quite a few of these emails and messages fro the $79 backers asking where it is. I thought I was pretty clear in the updates that only the $85 ones had shipped so far?

No worries, I honestly can't remember which option I ordered, I thought 85, but I couldn't bother enough to look it up. Coming to think about it, I was just a few numbers too late to order a signature version so it was probably the el-Cheapo version 8)

Since Afrikaans is phonetically much like Dutch, I am curious what you mean by that. "I get a hole in what kind of rodent?" ???

(maybe a response by PM if it goes too much off-topic from this subject)

Watch Full Metal Jacket, and the voice and tone of the instructor. This is about as close as you get to a translation that is polite. Not fun to be on the receiving end, and I got a lot of that.... Drill instructors get worse the higher up in rank they get, and if they went on officers course as well you do not want to be on that receiving end. Was an interesting day when he took our instructors for some corrective drilling, we had to carry them to bed afterwards.

Only thing missing were the 4 plastic case screws. That often happens with Australian made goods.... things are never quite right. Not a big problem in this case (excuse the pun), I should have some screws around here to do the job.

Only thing missing were the 4 plastic case screws. That often happens with Australian made goods.... things are never quite right. Not a big problem in this case (excuse the pun), I should have some screws around here to do the job.

Same here. Although given I probably enough odds and sods screws to last a lifetime, I'm not going to worry about it :)

I received unit #564 today. It was mailed on 3/28/14 and arrived in perfect condition in the USA 10 days later. Packaging was done very well and the shipping label was placed nicely (thanks Mrs EEVblog and Sagan :-+)

Received unit 570 today in Austin, TX. Shipped 28 March. Even got four (yup four; counted 'em twice) screws for the box. Now need to find a CR2032 battery so I can have a measure-off with my original µCurrent. :-+

Can anyone point me to a pdf of some instructions for this? Also, does it take one CR2032 or two? Thanks.

It's a current meter, you use it like any other current meter (beware scope connected output grounding of course).The output equals the V/A ratio printed on the silkscreen.Original article is here:http://alternatezone.com/electronics/ucurrent/uCurrentArticle.pdf (http://alternatezone.com/electronics/ucurrent/uCurrentArticle.pdf)

Can anyone point me to a pdf of some instructions for this? Also, does it take one CR2032 or two? Thanks.

It's a current meter, you use it like any other current meter (beware scope connected output grounding of course).The output equals the V/A ratio printed on the silkscreen.Original article is here:http://alternatezone.com/electronics/ucurrent/uCurrentArticle.pdf (http://alternatezone.com/electronics/ucurrent/uCurrentArticle.pdf)

Thanks for the link, though you didn't have the SHORT function in the model referenced there. What does that do? Short around the shunt resistor to bypass it, removing the uCurrent from the circuit? Also, can you confirm that this model has the same current ranges as the original? Thanks.

Thanks for the link, though you didn't have the SHORT function in the model referenced there. What does that do? Short around the shunt resistor to bypass it, removing the uCurrent from the circuit? Also, can you confirm that this model has the same current ranges as the original? Thanks.

Both are explained on the Kickstarter page linked in the first post of this thread.

Finally got around to checking mine today. Not good at all!!!!!!! :--Erratic jumpy readings -10mV to +2mV from my 1mA source (DMMCheck Plus calibrated to 1.0003mA)My Agilent reads the source as 1.000mA (see pic), battery in uCurrent is rayovac CR2032 reading 2.96v, changed battery to GP reading 3.27; and still the same issues.

Reflow R1 and clean the switch as well, using a good contact cleaner. and then operate it about 5 times end to end to get the wiping contacts clean. That should help.

There is what looks like a cracked solder joint on R1 sense lead, which would cause this error. If more units have this then it will need attention. Will check my one when it arrives ( hopefully real soon now) in the post.

There is what looks like a cracked solder joint on R1 sense lead, which would cause this error. If more units have this then it will need attention. Will check my one when it arrives ( hopefully real soon now) in the post.

Dave did point out this on the first batch. This must have been one which was marginal and cracked during transit. AFAIK this issue has been resolved with later production units as they tweaked the process to take care of it.

There is what looks like a cracked solder joint on R1 sense lead, which would cause this error. If more units have this then it will need attention. Will check my one when it arrives ( hopefully real soon now) in the post.

Dave did point out this on the first batch. This must have been one which was marginal and cracked during transit. AFAIK this issue has been resolved with later production units as they tweaked the process to take care of it.

No, it's not working. I've hit it twice with the solder gun and still it bounces around. Is this leaded or lead free solder?

Lead free.Sorry you got a dud :( Obviously it would have passed the tests ok.I can't see anything wrong with the solder joints, but 2D photos aren't very useful.The only other thing I can think of is that the assembler has reported a few dud switches, so perhaps that would be it. I have not investigated the exact mechanism of the failure yet though.If you can confirm that then I can ship you some replacement switches. Heck, I'll ship you a replacement board, email me your snail mail address.

No, it's not working. I've hit it twice with the solder gun and still it bounces around. Is this leaded or lead free solder?

Lead free.Sorry you got a dud :( Obviously it would have passed the tests ok.I can't see anything wrong with the solder joints, but 2D photos aren't very useful.The only other thing I can think of is that the assembler has reported a few dud switches, so perhaps that would be it. I have not investigated the exact mechanism of the failure yet though.If you can confirm that then I can ship you some replacement switches. Heck, I'll ship you a replacement board, email me your snail mail address.

I switch to uA range and my DMM to V (not mV range) and got a reading of .9995 My source is 1.0003mA so:1.0003mA (+/-)0.05% = uCurrent output of 0.9998V - 1.0008VThen you add in the meter (+/-)0.05%+5 count you get a range of:0.9988V - 1.0018V. So if my math is right; in the uA range I am getting a reading within the limits of the uCurrant and my Agilent U1272A DMM. It is just not working right in the mA range.

µCurrent Gold with SN #1003 arrived on 2014-04-25 (send date 2014-04-14). Quality is very good, no issues with insuficient solder wetting or tomb stoning.(http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/?action=dlattach;attach=91202)It works well - see picture with test of crude CC load.

I switch to uA range and my DMM to V (not mV range) and got a reading of .9995 My source is 1.0003mA so:1.0003mA (+/-)0.05% = uCurrent output of 0.9998V - 1.0008VThen you add in the meter (+/-)0.05%+5 count you get a range of:0.9988V - 1.0018V. So if my math is right; in the uA range I am getting a reading within the limits of the uCurrant and my Agilent U1272A DMM. It is just not working right in the mA range.

If uA range work and the mA range doesn't then it can only be the switch or the mA shunt resistor, there is nothing else. Check the connections on those, something has to be wrong somewhere.I'll be shipping you another one anyway.

Yupp, thanks to Dave for being so clever to declare a value of only $25. Even if German customs would falsely calculate with US$ instead of AUS$, this would only translate to roughly EUR 18. In Germany, any imported goods with a value of up to EUR 22 (incl. shipping costs) is exempted from custom fees and from import sales tax. I guess many other (European) countries have similar exemptions.

[...]In Germany, any imported goods with a value of up to EUR 22 (incl. shipping costs) is exempted from custom fees and from import sales tax. I guess many other (European) countries have similar exemptions.

In Lithuania (and I suspect in most EU countries), for example, you have to pay VAT (21% in Lithuania) if parcel value is higher than ~22 EUR (30 USD). Custom fee is calculated for product of value ~46 EUR (64 USD) or higher.Fees are on the high side in my opinion, but the main problem is that any shipping adds to total value base for these taxes. This may lead to situations where shipping and taxes are >100% of original price of the item.

EDIT: Custom duties are applied only to import form non EU counties. VAT applies for goods from EU and non EU.

just wondering if dave has a stash of these for sale? or when is the next batch available?thank you

More were supposed to turn up today (they haven't), and more tomorrow. So that should finally fulfill the kickstarter orders and I will have spares for general sale.I do still need to set up a shopping cart that integrates with my eParcel system though.

More were supposed to turn up today (they haven't), and more tomorrow. So that should finally fulfill the kickstarter orders and I will have spares for general sale.I do still need to set up a shopping cart that integrates with my eParcel system though.[/quote]

can i have one please, please............how much are they and how can i order onethank you

Mine arrived last week here in Germany, found it in the post box Friday night.

I did some tests today, a function generator in series with a 100k resistor on the nA setting.Response is flat to 200kHz, 3dB down at about 280kHz. In the time domain there is a little bit of overshot.See attached pictures.

Mine arrived many weeks ago, tested and working well. I see the battery LED is on all the time, presumably to stop you leaving it on like the old one (which I was always doing). Unfortunately, I still leave this one on too. What can you do??? Nice try though.....

Don't turn it on. Take it apart! ;) Void the warranty. >:D Try to make it better. :D Put it back together. :-+

I received my Kickstarter uCurrent Gold, serial number 798, in Toronto, Canada on May 13. It was mailed on May 2.

I've spent some time making changes to it:

Change on-short to off-short

Lower the LED brightness

Add some input protection when off

Increase the positive measurement range

Lower the case

Here are some details:

I don't see a need for it to be powered on when the power switch is in the "SHORT" position. It will just read 0 anyway. I cut the trace between SW2 pins 1A and 3A.

I found the "BATT OK" LED to be too bright for my liking, even when the battery voltage was near the low limit. I replaced the 270R resistor, R4, with a 470R one. With 470R, the LED current is between 1.3mA and 1.9mA and it's still plenty bright. Since the LED uses more power than everything else combined, I estimate that the battery will probably now last 30% to 50% longer or maybe even more.

It's difficult to know what kind of protection the inputs of U1, a MAX4239, have. The datasheet only specifies the maximum input voltages. It doesn't say what happens, or how much current is safe, if these voltages are exceeded. I didn't want to affect the circuit when powered on, but I figured it couldn't hurt to add back-to-back 1N5820 3A Schottky diodes across the inputs when the power is off. To do this, I added a jumper between SW2 pins 2B and 3B and put the diodes from SW2 pin 4B to the big trace connected to the minus side of R1. Note that this does nothing to protect the input when the power is on. I've discussed this previously in this post:http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg376311/#msg376311 (http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg376311/#msg376311)

I don't expect I'll often use the uCurrent to measure AC or other currents that swing both positive and negative. I felt it would be nice to have a larger range for single polarity measurements. I realised that this could be accomplished by shifting the virtual ground, by changing the values of R6 and/or R7. This would give a larger range for one polarity at the expense of lowering the range for the other polarity.

Rather than just hard wire a new ground level, I decided to use a switch. I bought a small 1P3T slide switch with the intent to switch another resistor in parallel with either R6 or R7. The three switch positions would allow the virtual ground remain centred, be shifted higher, or shifted lower. However, after examining the datasheet for U2, a LMV321, I noticed that the virtual ground was already close to the high end of the input common mode voltage range. Shifting the virtual ground higher any significant amount, to extend the negative range, would not be possible. Even if U2 could do it, U1 and U4 have similar limitations.

Since I already had the three position switch, I decided to add two more selections that increase the positive range. Position 1 leaves the circuit unaltered, with the original range of +/-1250mV. Position 2 switches a 30.1K resistor in parallel with R7, for a range of at least +2000mV and -400mV. Position 3 switches a 2.49K resistor in parallel with R7, which shifts ground almost to 0, for a range of +2400mV but only about -50mV. You can't bring the virtual ground all the way to 0 because even though the LMV321 is specified as having a rail to rail output, it can't really go all the way to 0 and neither can the U1 and U4.

The switch I used is a NKK SS14MDP2. I drilled holes close to the edge of the board, between the output terminals. Unfortunately the switch covers up the word "VOLTAGE" of "VOLTAGE OUTPUT". I had to remove the circuit board copper around the holes to prevent shorting the pins. I also had to relocate the serial number sticker (did I void my warranty? :-\ ). The best place I found for this sticker ended up partially covering the graphic of Dave (Sorry Dave :-[ ). I plan to put a label on the output side of the case, to indicate the range values.

I don't intend to add larger batteries or anything else under the circuit board, so I cut the case down to a height of about 18mm. I could've gone even lower except for the way I mounted the protection diodes. (BTW, my uCurrent came with the black case screws.)

For all those who have asked, the µCurrent is now available from my new store:https://eevblog.myshopify.com/ (https://eevblog.myshopify.com/)

Does this already include shipping? Quick browse through or search didn't reveal this secret. Most annoying thing when checking a store on web that doesn't clearly state what are the shipping costs. I assume it's already included in the price for international shipping? Or still Add $12 AUD to ship outside Australia?

Did you forget:http://clickingbad.nullism.com/ (http://clickingbad.nullism.com/) ?Golden rule of moving product: Distribution, Distribution and DistributionI think it was one amp hour show. You get less profits if someone else does it, but you are able to move more product and worry less. And you get the advantage of people getting to order more things at once from a store they want to order from.

Any chance you will get a HUGE batch of ucurrent golds in the future and sell them at a discounted price? So people who want one but don't have the extra will have no excuse to get it while it's cheap? Maybe when you hit 1000 episodes, or 200k subscribers? Doesn't have to be crazy cheap, just below the pain threshold.

I found the "BATT OK" LED to be too bright for my liking, even when the battery voltage was near the low limit. I replaced the 270R resistor, R4, with a 470R one. With 470R, the LED current is between 1.3mA and 1.9mA and it's still plenty bright.

I decided that the LED was still a bit too bright for me with the 470R R4, so I've now put in a 1K. This is fine for me, although a 1.2K or even 1.5K would probably still be bright enough.

With 1K, the LED current is 1mA with power at 3V. It drops to 0.72mA at 2.65V, which is the threshold where my unit's LED goes out.

I measured my unit's total current draw, with nothing connected, and found it to be 2.28mA at 3V and 1.95mA at 2.65V. Calculating the current for everything other than the LED, by subtracting the LED current, you get 1.28mA at 3V and 1.23mA at 2.65V.

For readings other than 0, additional current will be drawn by the gain resistors of U1 and U4. E.g. at 1V output the unit will draw an additional 0.11mA

For aussies, no, the same price.For international, yes, cheaper than Kickstarter.Because when I ran the Kickstarter I expected to pay a high price for international shipping, but I have now spent the last several months setting up and refining an Australia Post commercial account that lets me get cheap international rates. It's actually now slightly cheaper for me to ship something international than it is to ship within oz.

Does this already include shipping? Quick browse through or search didn't reveal this secret.

Yes, free shipping anywhere in the world.Extra if you want overseas tracking.

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Did you forget:http://clickingbad.nullism.com/ (http://clickingbad.nullism.com/) ?Golden rule of moving product: Distribution, Distribution and Distribution

Not all rules apply to all situations.I am in a position where I have a large audience, and a product niche enough that "passing trade" sales on distributors websites are small. So there is no benefit in having distributors from that point of view.Also, I just spend many months and a lot effort setting up a commercial account and a system that lets me ship stuff efficiently and cheaply. To now not take advantage of that would be very silly.

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You get less profits if someone else does it, but you are able to move more product and worry less.

You get a LOT less profit. In fact the distributors make more on the product than I would.Also, the customer likely ends up paying more for the item, becausea) I can offer free shipping anywhere in the world and absorb the cost into my larger marginb) I can't sell at a crazy low price to the distributor and make a reasonable return from it, so it's likely for the distributor to sell at a higher price than me in order to maintain the >40% markup they want.Either way the customer loses.The only way the customer gains by me using a distributor is that they can get the product quicker locally, and/or potentially bundle shipping with other stuff they want.

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And you get the advantage of people getting to order more things at once from a store they want to order from.

That's not an advantage for me.

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Any chance you will get a HUGE batch of ucurrent golds in the future and sell them at a discounted price?

Doubt it, because the price does not really come down with more volume. I've already hit the price deduction point.

Is there general topic for new EEVblog store? Just noticed main eevblog.com page has link to store but it's the old store http://www.eevblog.com/shop/ (http://www.eevblog.com/shop/) while new store is at https://eevblog.myshopify.com/ (https://eevblog.myshopify.com/)Maybe also include µrulers with all different colours in your store? Or time for new crowdfunding campaign, this time Indiegogo, maybe even flexible funding?

Just received my uCurrent, however having a few issues, and also have a few questions. First, the issue I am having is that as soon as I put in a 2032 battery and turn it on, the battery drains in about 60s. I am using a BR2032, I know it is rated at less mAh than a CR2032, however I assume that is would still last longer than 60 seconds. I have since powered it by 3AAA so I could at least try to use it, but I am measuring 7mA of current draw when it is turned on. Does this seem normal (using 1.2V eneloop batteries for reference).Now my questions are, can I just connect the output directly to an oscilloscope? I have seen a couple of references about connecting it and being careful about something, but not exactly sure what that means. The other question is, I actually need to measure a current range from +-10mA. This means on the 1mV/mA range, I at the very bottom of the range, however I can't go up to the next range because I am then over the limit of +-1250uA. Would I be able to remove the 10R resistor (R9) and replace it with say a 1R or .1R and reduce the range on the 2nd setting? I was hoping to use this device to measure the current that is applied to subjects during neurophysiology experiments, because at the moment we are using hall effect sensors and they have not been that reliable etc.Sorry if this is the wrong thread to post in, but does not seem there is a dedicated ucurrent thread addressing issues etc. Thanks in advance.

First, the issue I am having is that as soon as I put in a 2032 battery and turn it on, the battery drains in about 60s. I am using a BR2032, I know it is rated at less mAh than a CR2032, however I assume that is would still last longer than 60 seconds.

The BR2032 also has a lower output voltage, of about 2.8V, than a CR2032 (about 3V). The relatively high current draw of the µCurrent is probably quickly pulling this down below the 2.65V threshold of the BATT OK LED. The battery probably isn't drained but it's unable to supply a high enough voltage. I'd try a fresh CR2032.

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I have since powered it by 3AAA so I could at least try to use it, but I am measuring 7mA of current draw when it is turned on. Does this seem normal (using 1.2V eneloop batteries for reference).

A fully charged Eneloop AAA will be at about 1.3V with a 7mA current draw, so 3 in series will be 3.9V. Dave measured 7.2mA from the LED alone at 4.5V and I've measured the rest of the circuitry to draw at least 1mA, so your measurement of 7mA total at 3.9V sounds about right.

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Now my questions are, can I just connect the output directly to an oscilloscope? I have seen a couple of references about connecting it and being careful about something, but not exactly sure what that means.

I'm guessing one of the references is one of my posts:http://www.eevblog.com/forum/testgear/is-there-a-video-on-the-proper-usage-of-the-micro-current-gold/msg449116/#msg449116 (http://www.eevblog.com/forum/testgear/is-there-a-video-on-the-proper-usage-of-the-micro-current-gold/msg449116/#msg449116)I would watch Dave's video that xquercus refers to in a following post:http://www.eevblog.com/forum/testgear/is-there-a-video-on-the-proper-usage-of-the-micro-current-gold/msg458742/#msg458742 (http://www.eevblog.com/forum/testgear/is-there-a-video-on-the-proper-usage-of-the-micro-current-gold/msg458742/#msg458742)

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Would I be able to remove the 10R resistor (R9) and replace it with say a 1R or .1R and reduce the range on the 2nd setting?

The 10K R2 is always in the circuit. To compensate for this, R9 is placed in series with R1 when on the µA range, which gives an overall resistance of very close to 10R. If you were to replace R9 with a 1R, you would get an overall shunt resistance of 1.0099R so have an error of about 1%. With a .1R you would get 0.101R. For proper readings R9 would have to be 0.9901R or 0.09R.

If you only need one range, I'd instead replace R2 (10K) with either the 1R or .1R that you propose and put the switch on the nA range. Note, though, that this would severely mess up readings on the other two ranges.

I am working on making test applications on ATE / "Automated Test Environment" machines and we get a lot of projects involving automotive electronics.On most of these projects the measurement of standby current consumption is essential and it's very important for our customers to ensure a correct standby current.

So I have pretty much taken the µCurrent design and changed it to fit my own needs.I plan to change the shunt depending on the actual application / the current that I want to measure.Amplification is x100 like the µCurrent and output voltage should be in the 1V range so that the 1V range of my voltmeter can be used.

First of all the output voltage should be ground referenced, thus a charge pump for generating negative OP amp supply is needed.

I also changed the OP-Amp to one that's easier to source for me and still offers quite good specs. I also don't need very high precision because we just need to ensure that the standby current consumption is "about right". It's more important to have reproducible measurements.

I also don't need multiple ranges. For high currents (active current of the DUT / "Device Under Test") i can just read the power supply.I just need a circuit that helps to measure currents in the 1 to 100 uA range.

I also added a "burden voltage limiter", basically a shunt regulator limiting the burden voltage to something of about 20mV regardless of the current.

I attached my circuit here and want to bring that last addition to your attention.Most loads (e.g. a microcontroller circuit) have high dynamic range current consumption.The load might stay in standby mode for most of the time, drawing only little current.From time to time the load will wake up and do something that consumes a lot more current.

Now if the µCurrent is set to 1250nA range (10k shunt resistor) then the load won't be able to wake up properly because the 10k shunt resistor is limiting the current to the load. And even if the circuit can wake up, the increased current draw of the load will cause the load voltage to drop.

For that reason i added that "burden voltage limiter". As soon as the burden voltage increases to something above 20mV the MOSFET will turn on and ensure that the load voltage won't drop.This way you also don't have to worry about setting the correct current range.

Though I am unsure of how much this will affect the actual measurement. I guess the OP-Amp IC4 in my circuit will have some small input current and the OFF-state resistance / leakage current of Q1 will also cause some error.

What do you think, does this circuit make sense?How big is the error introduced due to that circuit? Any ideas to reduce the error? Maybe I can make a better choice of components for this?Can this be a possible addition to the next µCurrent? If the effect on the measurement is too big it can be made so, that it can be switched on / off.

But where is the documentation? Obviously you added those diodes for greater protection, so it's pertinent that documentation explains what pitfalls to avoid when using the uCurrent. Surely someone must have put together some documentation on the uCurrent by now, but I am not finding it. Do you have access to that?

But where is the documentation? Obviously you added those diodes for greater protection, so it's pertinent that documentation explains what pitfalls to avoid when using the uCurrent. Surely someone must have put together some documentation on the uCurrent by now, but I am not finding it. Do you have access to that?

It is a really nice precision current to voltage converter, I have one and I can recommend it. It is obvious how to use it, but looks like you are right, I can't find any beginners documentation either. And there are some pitfalls, for example when using the nA range you have to take care that it doesn't oscillate which can happen with long cables, as I've discovered:

Intuitively, it seems obvious how to use it, but that would be true for the ON switch position. But for the SHORT position, I am still not clear on that.

I only measure DC, from 0V to a max of about 33V. I have a $2000 6.5 digit Fluke 8845A and it works great to measure current down to about 1uA, but the nA range is terrible. When the leads are floating I see 23nA on the meter. So I want accurate nA measurements, especially to check low power designs with PIC MCUs.

I've also been reading about button cell batteries dying in 60 seconds. It's not clear if people are using new or old cells. Does the kit come with the AAA battery holder? Even so, I've been reading that increasing the voltage will increase sensitivity and noise too, and I am not sure if I want to deal with that. Your capacitor fix might work though.

The short position does what the name says, it shorts the input shunt, so that there is 0 V burden voltage for your circuit (of course, you'll have 0 V output voltage in this position, too).

I guess measuring nA is tricky, no matter what instrument you use.

I think my uCurrent came with the AAA battery holder, I just had to solder it. The CR2032 coin cell battery I used before lasted hours and was still the first battery when I replaced it with the battery holder for greater output voltage and even longer battery life. But I don't need it often, I guess I'll have to replace the batteries in some years now :)

The short position does what the name says, it shorts the input shunt, so that there is 0 V burden voltage for your circuit (of course, you'll have 0 V output voltage in this position, too).

I see... You can leave uCurrent connected in the circuit, and sliding the the switch to the SHORT position will make it as if uCurrent were not connected to the circuit at all.

Well, thank you for the advice. It seems that replacing R4 to reduce LED brightness (or remote the LED altogether), combined with the 3 AAA battery pack mod would be prudent for everyone. I will consider both. Not sure about the dual Schottky diode mod that another use reported though. It seems to only help if the uCurrent is OFF, but I would want protection when it's ON. I can't tell you how many times I've blown those stupidly expensive 400mA fuses in the Fluke Benchtop meter!

Right, the schottky diode mod only protects the OpAmp inputs when it is in off position. I don't know if this is necessary, even if voltage is applied to the inputs. And usually it is always on anyway when I use it, so this wouldn't be a problem.

But it has no over current protection, it is intended for sub 1A measurements and where you know it can't be higher, e.g. because you use a power supply with current limit. And you can easily destroy the 10 ohm resistor in the uA range. E.g. apply 5 V, which results in 500 mA, so 2.5 W for the poor little 0805 resistor and the magic smoke will escape. Or you could destroy the OpAmp, if you apply a too high voltage with the nA range instead of measuring the current in series, because the 10 k shunt resistor would survive it, but unlikely that the OpAmp survives it, e.g. if you short accidentally 30 V. For the mA range I think you would need a lot of amps to vaporize the 0.01 ohm shunt, because the cables etc. might absorb most of it. The switch might blow up first in this case.

I guess most of it could be solved with a fuse and some big diodes in parallel to the shunts, but this might affect the accuracy.

PS: I think Dave's upcoming new multimeter will have a nA range, too, and of course all the proper input protections. But if you have already a Fluke 8845A, you probably don't need it, and just the uCurrent would be less expensive.

The "SHORT" setting allows you to put the uCurrent into the circuit with the end result that it is actually not in the circuit insofar as 50mA or even 1A could flow through your tapped test point without problem or blowing up the uCurrent. So is it better to start by putting the uCurrent into SHORT mode and then attached it to the circuit (with power off, of course), and then switch to ON (with the appropriate Amperage range selected, of course) to start testing? Or is it always best to start with the uCurrent OFF and then connect it and then switch to ON?

Honestly, I've accidentally blown about 5 expensive 400mA fuses on my Fluke 8845A through the years, and that was when I was being cautious. So without any fusing at all, and in light of the price point on this little uCurrent gadget, I would like to be darned sure that the way I use it is not going to fry my investment for a very long time, if ever.

I don't think it matters much, but sounds good to keep it in short setting first. I have to admit, I never blew up a fuse in one of my multimeters so far, but I'm just a programmer and do some retro electronics and digital electronics with microcontrollers etc., so currents are low most of the time, and additionally limited by the power supply. If you blow up your fuse often, you might add a fuse to the uCurrent, too. Dave describes a typical circuit for it here:

You would need only the 600 mA fuse and a big rectifier after it, or two big anti-parallel diodes. I think this will protect it from over-current and over-voltage (to some degree, don't short 220 V mains with it). Might be difficult to mount it inside. Maybe the fuse inline with one measurement cable, and then the diodes soldering to the terminals on the back? But I have no idea what diodes you can use and how it affects the measurement. I guess it is not that much of a problem, because the leakage current of diodes are very low compared to the shunt resistors? And might be good to use a "fast" fuse.

You can read all the details about it in the Supporters Lounge (you get access to this exclusive club as a Patreon (https://www.patreon.com/eevblog/)), but he doesn't want it to be public at this time.

Thank you, Frank. Very informative. But yet more reason to have that Fire Sale I proposed, clear out old uCurrent Gold inventory, and then offer an updated uCurrent with all the major hacks people all incorporation (protection, reduce LED brightness, use a 3-AA battery pack by default, etc). That mod of the uCurrent probably debut faster than a complex multi-meter built from the ground up.

By the way...

While Googling on the topic of nA measurements, I came across the following page and found the comments section of interest:

Burden Voltage is the voltage produced across a DVM’s internal current shut when it is in Amperes mode. Burden Voltage is named incorrectly. The burden units are strictly V/A (the voltage produced across the shunt for a given amount of current going through it). Units V/A equal Ohms, which is the resistance of the current shunt. So the strictly correct term is Burden Resistance, but the incorrect term Burden Voltage is now simply accepted as the historical norm.

Interesting idea, but burden voltage, or whatever you want to call it, is too high for many measurements. E.g. for 60 nA and 10 megohm input resistance it is already 0.6 V. Too much if you want to check low voltage / low power microcontrollers. But it could be useful if you want to measure below 10 nA. But I guess you can't expect too much accuracy.

...for 60 nA and 10 megohm input resistance it is already 0.6 V. Too much if you want to check low voltage / low power microcontrollers. But it could be useful if you want to measure below 10 nA...

My entire purpose for buying something like the uCurrent Gold is to take nA measurements in conjunction with PIC MCUs. Let's say you want to calculate the internal impedance of a PIC input pin. We know the equivalent resistance is very high because it is the leg of a FET inside the PIC. But does it work out to be 10M? or 100M? or greater? Well, if we could put a precision Ammeter between say an external pull-up resistor and the PIC's input pin, we could check how much current flows through that pull-up into the PIC. I've tried it with my Fluke 8845A, but again, with both probes disconnected the Fluke shows 23nA or so. And taking measurements in a variety of ways indicates to me that current to be 100nA or less. So something like a uCurrent would help measure tiny current more accurately, which in turn can help find out the internal resistance of input pins, among other things.

But again, despite the fact I've been taking measurements on PIC circuits (12V input voltage dropped to 3V or 5V via voltage regulator), I've connected my Fluke meter incorrectly by accident several times through the years and have had to replace a few 400mA fuses. That's why if I buy a uCurrent I would need to mod the thing to protect against my own stupid mistakes. While rare, mistakes with a uCurrent would be much more costly than a costly Fluke 400mA fuse!

I didn't want to affect the circuit when powered on, but I figured it couldn't hurt to add back-to-back 1N5820 3A Schottky diodes across the inputs when the power is off. To do this, I added a jumper between SW2 pins 2B and 3B and put the diodes from SW2 pin 4B to the big trace connected to the minus side of R1. Note that this does nothing to protect the input when the power is on.

MLXXXp, can you give us some example situations, when the power is switched OFF, that would potentially destroy the uCurrent Gold in its stock condition (i.e., WITHOUT those two diodes)?

And for the rest of you uCurrent Gold users, have any of you ever destroyed your uCurrent when the power is OFF?

MLXXXp, can you give us some example situations, when the power is switched OFF, that would potentially destroy the uCurrent Gold in its stock condition (i.e., WITHOUT those two diodes)?

Even when the µCurrent is switched off, whatever the shunt resistor(s), R1, R2, R9, selected by the range switch will still be across the inputs. Any current flowing through the resistor(s) via the inputs, that causes the wattage to exceed the resistor ratings could potentially damage the resistor(s).

Also, even with the µCurrent switched off, the voltage across the shunt resistor(s) will also be impressed across the inputs of U1, but though R12, R5 and other circuitry, such that the actual current path is difficult to determine. The MAX4239 datasheet and any other documentation I've found doesn't say much about the maximum ratings for the inputs. It only states (VGND - 0.3V) to (VCC + 0.3V) but says nothing about how much current the inputs will tolerate when these voltages are exceeded. Therefore, it's difficult to predict the voltage across the shunt resistor(s) which would cause damage to U1 or other components in the path, but damage could occur if whatever voltage that happens to be were exceeded.

Strikes me that having back-to-back diodes might reduce the accuracy slightly on what is a very accurate instrument, by way of introducing a small parallel leakage. The opposite concern though, is that without diodes an overload may have decalibrated your µCurrent by burning out the shunt. You might not be aware of this for some time, and could be taking a whole load of incorrect measurements as a result.

If the diodes are heavily overloaded they will typically fail s/c, in which case you will be aware that there is a problem.

There is obviously a balance to be struck here, between having no protection and a very vulnerable instrument, to having the OTT protection most DMMs have, which raises the burden voltage to ridiculous levels.

Bought a couple of these back in 2014-15 (don´t remember) and never used them. Now with the IOT I think I'll put them to good use.

But I have a question:

In http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg432824/#msg432824 (http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg432824/#msg432824) it says that he used 4xAAA batteries, and the device uses one coin cell (3V if I remember right). Can the device support 6V?

I don´t need negative currents so maybe I´ll take MLXXXp suggestions and move that voltage up a bit. Just need to find those resistors.

Thanks in advance and hopefully Dave will upgrade this unique device and add those new features.

In http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg432824/#msg432824 (http://www.eevblog.com/forum/crowd-funded-projects/current-gold-on-kickstarter/msg432824/#msg432824) it says that he used 4xAAA batteries, and the device uses one coin cell (3V if I remember right). Can the device support 6V?

I believe the 4xAAA batteries are powering the constant current load that the µCurrent is measuring, not the µCurrent itself.

The op amps in the µCurrent are rated 5.5V maximum, so I wouldn't power the µCurrent at anything higher than that. Also, if you increase the µCurrent's supply voltage, you run the risk of damaging the TPS3809 voltage supervisor IC due to increased LED current.

Sorry again for the double post, can't find a way to attach an image to an old post.

This is the current measured with an Analog Discovery (version 1) and a 10 \$\Omega\$ @1%, but I would like to redo the measurement with a RIGOL oscilloscope and the uCurrent. The Analog Discovery (version 1) has only 16k points.

I was wondering if it's still possible to get a ucurrent gold? I've looked at every link I can find and they all say it's out of stock? Is the project currently having backlogs or demand has dropped to the point it's no longer being produced?

Or as was mentioned one page back did they have a fire sale to get the old units out and an update is in the works?

They are Mike, they arrive to Dave prepacked in padded envelopes ready for dispatch which makes dispatching fairly simple for both of us. It's just the time it takes between batches being made as you never know just how popular they are going to be so ordering too many can lead to a nasty surprise ? i think Dave is surprised so many have sold.

You don't see this with a multimeter. But maybe not a problem, if you just want to measure sleep and idle currents. But the interesting things happens when you transmit wireless data with your ESP8266.

PS: when you use a scope, you should power it from a battery, or isolated power supply, to avoid ground problems.

I have to measure currents from mA down to nA. Hence, without code modification (only sleep or only running) uCurrent is of no use to me.I am currently testing another similar to uCurrent device called Current Ranger with auto-ranging. Very convenient for Arduino+nrf24l01+ or ESP8266/ESP32

I would like to electronically control the range selection between mA and µA modes (nA mode is not needed). I am thinking of replacing the SW1 with two MOSFETs – one between 1A and 2A and another one between 2A and 3A. Will this kind of modification affect the measurement results? Is there anything I should take into account when selecting MOSFETs?

I would like to electronically control the range selection between mA and µA modes (nA mode is not needed). I am thinking of replacing the SW1 with two MOSFETs – one between 1A and 2A and another one between 2A and 3A. Will this kind of modification affect the measurement results? Is there anything I should take into account when selecting MOSFETs?

EDIT: Also, making a modification like this is a whole topic that deserves a thread on its own. I strongly suggest making a separate thread for this. Just to close off this thread quickly, if you don't want the nA range then you can turn the right hand side of the switch into a plain wire (as the uA and mA settings make identical connections on that side), and you can replace the left hand side with N-type MOSFETs (you're lucky because nodes 1A and 3A are basically shorted to J2.) You need to pay special attention to how you will drive the gates of the MOSFET though, as J2 is at virtual ground, not at circuit/battery ground. V+ is only 1.5V above VGND, so you're going to need some sort of charge pump or other power supply to turn any normal MOSFET on.